{ "response": { "Key": "DEN-LIS", "orig": { "code": "DEN", "type": "airport", "city": "Denver", "fullCity": "Denver, Colorado", "airport": "Denver Intl Airport" }, "dest": { "code": "LIS", "type": "airport", "city": "Lisbon", "fullCity": "Lisbon, Portugal", "airport": "Humberto Delgado Airport" }, "faq": { "q0": { "question": "What is the typical flight duration from Denver to Lisbon?", "answer": "There are no nonstop flights from Denver (DEN) to Lisbon (LIS). With one stop, typical total travel time ranges from 12 to 15 hours, depending on the layover city. Common layovers include Newark, New York JFK, or European hubs like London or Frankfurt; airlines like United, TAP Air Portugal, and Lufthansa offer these routes." }, "q1": { "question": "Are there any direct flights from Denver to Lisbon?", "answer": "There are no nonstop flights from Denver to Lisbon. The quickest one-stop connections go through London Heathrow (British Airways, about 13h 30m total) or Washington Dulles (United, roughly 13h 15m), with other options via Philadelphia (American), Montreal or Toronto (Air Canada), and Frankfurt or Munich (Lufthansa). Most routings take between 13 and 15 hours including the layover.", "methodology": "Airlines and weekly frequencies are compiled from our flight-schedule database, which combines published airline timetables, U.S. government schedule data from the Bureau of Transportation Statistics (BTS), and observed flight operations from the EUROCONTROL/OpenSky Open Performance Data Initiative (OPDI). We count each operating carrier's scheduled weekly departures and the days it flies; where there is no nonstop service, connecting carriers are identified by linking scheduled nonstop segments through common hub airports. Where a median fare is shown for a carrier, it reflects the real fares Priceline users found on this route in the last 72 hours. Carrier service and weekly frequencies are summarized from our flight-schedule database, which draws on published airline timetables, U.S. government schedule data, and observed operations from the EUROCONTROL/OpenSky Open Performance Data Initiative (OPDI). Where available, on-time and cancellation rates come from the U.S. Bureau of Transportation Statistics (BTS) Airline On-Time Performance dataset, and typical fares from the U.S. DOT Airline Origin and Destination Survey (DB1B), a quarterly 10% sample of tickets sold. Aircraft types are taken from the equipment each operating carrier schedules on this route, drawn from published airline timetables and airline equipment schedules in our flight-schedule database. They describe typical scheduled aircraft and can vary with seasonal or day-of-week assignments and last-minute equipment swaps.", "toolsUsed": [ "route_airlines", "flight_schedule", "route_aircraft" ] }, "q2": { "question": "Are there visa requirements to travel from Denver to Lisbon?", "answer": "Yes, visa requirements depend on your nationality. For U.S. citizens traveling to Portugal, no visa is needed for stays up to 90 days in the Schengen area, but starting in 2025, you'll need an ETIAS authorization. Portuguese citizens and other non-U.S. nationals may need a visa to enter the U.S. unless they are from a Visa Waiver Program country, in which case an ESTA is required. Always check the latest rules before travel." }, "q3": { "question": "What are the ground transportation options in Lisbon?", "answer": "From Lisbon Airport (LIS), the Aerobus shuttle is the most popular and quickest way to the city center, with Line 2 reaching the historical center in about 25 minutes and Line 1 taking around 40 minutes; both run every 20–25 minutes and cost €4 for a 24-hour pass. Public buses (routes 5, 22, 44, 45, and 83) are also available and are the cheapest option. Taxis are readily available at arrivals and departures, but always confirm the fare beforehand due to airport surcharges and luggage fees. There is no direct train from the airport, but a short taxi ride connects to nearby rail stations like Gare do Oriente for access to the metro and national rail services. Ride-share services and car rentals are also available, though the Aerobus remains the most-used option for its directness and value.", "toolsUsed": [], "references": [ { "url": "http://lisbon-lis.airports-guides.com", "title": "Lisbon Portela Airport (LIS) Information: LIS Airport in Lisbon Area, Portugal" }, { "url": "http://www.lisbon-lis.airports-guides.com/lis_airport_transport.html", "title": "Lisbon Portela Airport (LIS) Travel, Transport: Travel at Airports in Lisbon Area, Portugal", "time_published": "2016-03-03T00:00:00Z" }, { "url": "https://www.lisbon-airport.net/", "title": "Lisbon Airport (LIS)" }, { "url": "https://lisbonairport.net/lisbon-airport-transfers/bus/", "title": "Getting to Lisbon Airport by Bus", "time_published": "2019-03-02T00:00:00Z" }, { "url": "https://lisbonairport.net", "title": "Lisbon Airport | Guide to Lisbon Airport (LIS)" } ] }, "q4": { "question": "When is the cheapest time to fly from Denver to Lisbon?", "answer": "The cheapest time to fly from Denver to Lisbon is in the low-season months of April, October, and November, with average fares around $856–$875. The most expensive period is the high-season stretch from May through August, particularly June when average prices peak at $1,459.", "methodology": "This 'good deal' estimate shows a representative best price for each departure date across roughly a 12-month window (about 3 months back and 9 months forward). It is built from real flight prices found by Priceline users searching this route, accumulated into a price history for each departure date. Rather than weighting all of that history equally, we apply exponential time decay so recent prices dominate — a price seen yesterday counts almost in full, one from about a month ago roughly a third, and prices from a few months back very little — giving a figure that tracks today's market instead of a stale long-run average. Clear price outliers are removed before any calculation, departure dates with no observations are filled in from nearby dates, and the resulting curve is lightly smoothed so it reads as a clean seasonal trend rather than day-to-day noise.", "toolsUsed": [ "seasonal_prices" ] }, "q5": { "question": "How far in advance should I book tickets from Denver to Lisbon?", "answer": "For flights from Denver to Lisbon, the sweet spot is booking roughly 9 to 11 weeks before departure, when average fares hover around $967. The absolute lowest price in recent data appeared about 65 days out, at $963. For peak summer and holiday travel, it's wise to lean toward the earlier end of that window or even a bit sooner, as demand can push last-minute prices higher.", "methodology": "This booking-window guidance is built from the same real flight prices found by Priceline users searching this route, re-grouped by how many days before departure each price was seen (from the departure day out to about 180 days ahead) across the route's price history. At each booking lead time we report the 25th-percentile price — the cheaper end of what travelers were quoted, rather than the rock-bottom minimum (which can be a fluke) or the average (which is pulled up by expensive last-minute fares). The buy-or-wait advice then applies a risk premium that grows as departure approaches, since seat availability shrinks and prices become less predictable; using that adjusted curve we flag windows where waiting is likely to save a meaningful amount (at least $20 or 5%) versus windows where booking now is the better call. Isolated single-day recommendations are filtered out, so the advice only reflects a window that holds for several days in a row.", "toolsUsed": [ "booking_timing" ] }, "q6": { "question": "Are overnight (red‑eye) flights available from Denver to Lisbon?", "answer": "No nonstop red-eye flights operate from Denver to Lisbon, but several one-stop itineraries have an overnight long leg. The most direct Denver-originating options include a Lufthansa departure at 5:40 PM from Denver to Frankfurt (arriving 11:15 AM) with a connection to Lisbon, and a similar Lufthansa overnight via Munich departing at 4:15 PM and arriving at 10:00 AM. Other connecting red-eyes route through US and Canadian gateways — for example, United via Washington Dulles departs at 10:25 PM and arrives Lisbon at 10:30 AM, and Air Canada via Montreal departs at 9:45 PM with a 9:20 AM arrival.", "methodology": "Red-eye flights are identified from scheduled local departure and arrival times in our flight-schedule database — built from published airline timetables and official schedule data, including U.S. Department of Transportation records for domestic routes — flagging services that depart late at night and arrive the following morning; for connecting itineraries the red-eye is based on the timing of the overnight long-haul leg.", "toolsUsed": [ "redeye_flights" ] }, "q7": { "question": "Which airlines usually operate this route from Denver to Lisbon?", "answer": "No airline flies nonstop from Denver to Lisbon, but several carriers offer convenient one‑stop connections. British Airways via London Heathrow is the most frequent, with about 13 daily departures, and United via Washington Dulles follows with roughly 8. Air Canada via Montreal and American Airlines via Philadelphia each appear around 5 to 6 times daily, while Lufthansa via Munich or Frankfurt and TAP Air Portugal via New York or Newark provide additional options. Typical per‑carrier fares are not available for this route.", "methodology": "Airlines and weekly frequencies are compiled from our flight-schedule database, which combines published airline timetables, U.S. government schedule data from the Bureau of Transportation Statistics (BTS), and observed flight operations from the EUROCONTROL/OpenSky Open Performance Data Initiative (OPDI). We count each operating carrier's scheduled weekly departures and the days it flies; where there is no nonstop service, connecting carriers are identified by linking scheduled nonstop segments through common hub airports. Where a median fare is shown for a carrier, it reflects the real fares Priceline users found on this route in the last 72 hours.", "toolsUsed": [ "route_airlines" ] }, "q8": { "question": "If I need a connection, what are common layover cities between Denver and Lisbon?", "answer": "Common layover cities between Denver and Lisbon include New York (JFK), Newark, Boston and Toronto. New York and Newark offer multiple daily flights to Lisbon with efficient connections, while Boston provides a shorter transatlantic hop. Toronto often features competitive fares and smooth transit for U.S. passport holders." }, "q9": { "question": "How reliable are on‑time departures on this route from Denver to Lisbon?", "answer": "On‑time reliability is moderate, with afternoon thunderstorms in Denver occasionally causing delays. Choosing early morning departures can improve your chances of leaving on schedule." }, "q10": { "question": "Which months have the best weather for traveling to Lisbon?", "answer": "May to June and September to early October offer sunny, mild weather and thinner crowds." }, "q11": { "question": "What documents should I bring with me to the airport when flying from Denver to Lisbon?", "answer": "Bring a passport valid for at least three months beyond your stay, any required Schengen visa or ETIAS authorization, proof of onward or return travel, a payment method for baggage and any necessary vaccination or insurance documents." }, "q12": { "question": "Which airport should I use in Lisbon?", "answer": "Lisbon has only one commercial airport, Humberto Delgado Airport, located about 7 km from downtown, serving all flights to the city." }, "q13": { "question": "How do I get to Denver Intl Airport from the city center?", "answer": "From downtown Denver, the A Line commuter train operated by RTD is the fastest and most popular option, running directly from Denver Union Station to the airport transit center in about 37 minutes. Public bus routes like the AT, AB, and 169L also serve the airport but take longer. Ride-share services such as Uber and Lyft, as well as taxis, provide door-to-door convenience at a higher cost, while driving and parking on-site is available with economy and garage options.", "toolsUsed": [], "references": [ { "url": "https://www.flydenver.com/parking-and-transportation/to-and-from/airport-transit-center/", "title": "Airport Transit Center | Denver International Airport", "time_published": "2026-02-24T17:09:34Z" }, { "url": "https://flydenver.com/connections/", "title": "Connections | Denver International Airport", "favicon": "https://flydenver.com/apple-touch-icon.png", "time_published": "2023-09-14T15:33:21Z" }, { "url": "https://en.wikipedia.org/wiki/Automated_Guideway_Transit_System_(Denver_International_Airport)", "title": "Automated Guideway Transit System (Denver International Airport)", "time_published": "2026-06-01T08:54:40Z" }, { "url": "https://en.wikipedia.org/wiki/Denver%20International%20Airport", "title": "Denver International Airport", "time_published": "2026-04-30T15:08:23Z" }, { "url": "https://www.faa.gov/?action=searchForAirport&airportcode=PSR", "title": "Federal Aviation Administration", "favicon": "https://www.faa.gov/themes/custom/faa/favicon.png", "time_published": "2026-07-17T12:00:00Z" } ] }, "q17": { "question": "What aircraft are typically used on flights from Denver to Lisbon?", "answer": "There is no nonstop service between Denver and Lisbon, so all flights involve a connection. On the long transatlantic leg, the most common aircraft are the Boeing 787-9, Boeing 777, and Airbus A350 (both -900 and -1000 variants), with the Airbus A330-300, A330-900neo, and A380 also appearing on some itineraries. The exact aircraft depends on the connecting hub and airline — for example, British Airways uses the A350-1000 via London Heathrow, United typically flies a 777 or 787 via its East Coast hubs, and Lufthansa fields the A350-900 or A380 via Frankfurt or Munich. Wi‑Fi and seatback entertainment are widely available on these long‑haul aircraft, though the specific offering varies by carrier.", "methodology": "Aircraft types are taken from the equipment each operating carrier schedules on this route, drawn from published airline timetables and airline equipment schedules in our flight-schedule database. They describe typical scheduled aircraft and can vary with seasonal or day-of-week assignments and last-minute equipment swaps.", "toolsUsed": [ "route_aircraft" ] }, "q18": { "question": "Which airline alliances serve flights from Denver to Lisbon?", "answer": "Star Alliance carriers dominate the Denver–Lisbon route: United, Air Canada, Lufthansa, TAP Air Portugal, and Turkish Airlines all offer one-stop connections. oneworld is also present through British Airways and American Airlines. SkyTeam has no operating carrier on this route, and JetBlue appears only as a short-haul feeder on one TAP itinerary but isn't a transatlantic operator and belongs to no alliance.", "methodology": "Airlines and weekly frequencies are compiled from our flight-schedule database, which combines published airline timetables, U.S. government schedule data from the Bureau of Transportation Statistics (BTS), and observed flight operations from the EUROCONTROL/OpenSky Open Performance Data Initiative (OPDI). We count each operating carrier's scheduled weekly departures and the days it flies; where there is no nonstop service, connecting carriers are identified by linking scheduled nonstop segments through common hub airports. Where a median fare is shown for a carrier, it reflects the real fares Priceline users found on this route in the last 72 hours.", "toolsUsed": [ "route_airlines" ] }, "q20": { "question": "What are the best airport lounge options when departing from Denver?", "answer": "At Denver International Airport, you'll find two main lounges: The Centurion Lounge in Concourse C and the Delta Sky Club in the Main Terminal, Concourse A. The Centurion Lounge is accessible with The Platinum Card® or Centurion Card and offers complimentary premium food, a full bar, and comfortable seating. The Delta Sky Club is available to Delta One, SkyTeam Elite Plus, or eligible cardholders and features premium food, a full bar, Wi-Fi, and flight monitors.", "toolsUsed": [], "references": [ { "url": "https://americanexpress.com/en-gb/travel/lounges/the-platinum-card/DEN", "title": "American Express Lounges at Denver International Airport | Amex GB", "time_published": "2026-05-03T00:00:00Z" }, { "url": "https://www.flydenver.com/", "title": "Denver International Airport | DEN", "favicon": "https://www.flydenver.com/apple-touch-icon.png", "time_published": "2026-06-02T21:34:27Z" }, { "url": "https://flydenver.com/at-the-airport", "title": "Exciting Things to Do at Denver International Airport", "time_published": "2026-02-18T15:39:31Z" }, { "url": "https://www.americanexpress.com/en-us/travel/lounges/the-centurion-card-idc-en/DEN/Delta-Sky-Club-Main-Terminal-Concourse-A-IgRTEiZDls/", "title": "Delta Sky Club at Denver International Airport | Amex US", "time_published": "2026-03-18T00:00:00Z" }, { "url": "https://carsandstays.delta.com/Denver-Hotels-Sleep-Inn-Suites-Denver-International-Airport.h23533743.Hotel-Information?categorySearch=any_option&chkin=2026-07-06&chkout=2026-07-07&destType=MARKET&destination=Denver%2C+CO%2C+United+States+of+America+%28DEN-All+Airports%29&latLong=39.74483000000001%2C-104.94829500000002&pwa_ts=1782175590171&referrerUrl=aHR0cHM6Ly9jYXJzYW5kc3RheXMuZGVsdGEuY29tL0hvdGVsLVNlYXJjaA%3D%3D®ionId=6139084&rfrr=HSR&rm1=a2&searchId=b9103c12-38ab-46f5-86a7-f3447411bdbe&selectedRatePlan=383244565&selectedRoomType=218717901&sort=RECOMMENDED&top_cur=USD&top_dp=126&useRewards=false&x_pwa=1", "title": "Sleep Inn & Suites Denver International Airport", "favicon": "https://carsandstays.delta.com/favicon.ico", "time_published": "2026-06-23T09:32:24Z" } ] }, "q21": { "question": "What is the baggage allowance on this route from Denver to Lisbon?", "answer": "Baggage allowance varies by airline and fare type. Basic economy tickets are restrictive and may not include a checked bag; standard international economy typically includes one checked bag and a carry-on. Premium cabins offer more generous allowances." }, "q22": { "question": "What cabin and seat options are typical from Denver to Lisbon?", "answer": "Flights from Denver to Lisbon typically offer Economy and flat‑bed Business class; Premium Economy is available on some connecting itineraries but not on all carriers." }, "q23": { "question": "Are same‑day changes or standby possible on this route?", "answer": "Policies differ by airline and fare; flexible and premium cabin tickets often allow same‑day changes or standby, while basic economy typically does not." } } } }