{"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": {"q1": {"question": "Are there any direct flights from Denver to Lisbon?", "answer": "There are no nonstop flights from Denver to Lisbon. The shortest one-stop routings typically connect through East Coast hubs like Newark (EWR) or Boston (BOS), with total travel time around 12–13 hours including a layover. United via Newark and TAP Air Portugal via Boston are common options, with fares starting around $711.", "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, flight times and distances for this route come 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). We report the days of the week and the departure times each carrier operates. The typical flight time is the median scheduled block time, given both per carrier and across all carriers on the route; where a schedule does not publish an elapsed time, it is derived from the scheduled departure and arrival times converted to UTC. Outbound and return times are computed by the same method, so the difference between them is directly comparable and reflects prevailing winds rather than any change in derivation. Distance is the great-circle distance between the two specific airports named, so an actual flown track is typically 2-5% longer. Where shown, on-time departure and arrival rates and cancellation rates come from the U.S. Bureau of Transportation Statistics (BTS) Airline On-Time Performance dataset, which covers U.S. domestic routes only; where a typical fare is shown, it comes from the U.S. DOT Airline Origin and Destination Survey (DB1B), a quarterly 10% sample of tickets sold. Cheapest prices are determined by finding the lowest fare Priceline users have found for the requested route and date in the last 72 hours.", "toolsUsed": ["route_airlines", "flight_schedule", "cheapest_flights"]}, "q3": {"question": "What are the ground transportation options in Lisbon?", "answer": "From Lisbon Airport, the most used option is the metro; the red line reaches the city center in about 20 minutes and a single ticket costs around €1.50. The Aerobus shuttle (Lines 1 and 2) runs every 20–25 minutes to the historical center, with a 24‑hour pass at €4. Taxis are available at ranks outside arrivals, with a 10–15 minute trip to downtown typically costing €10–15 plus luggage surcharges. Ride‑share services like Uber and Bolt also operate from designated pickup areas, often slightly cheaper than taxis. Car rental desks are in the terminal, but driving in central Lisbon is not recommended due to narrow streets and limited parking.", "toolsUsed": ["article_lookup"], "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 months to fly from Denver to Lisbon are April, November, and October, with average fares around $855–$863. The most expensive months are June, July, and May, where average prices climb to $1,185–$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 Denver to Lisbon, the best fares are typically found when booking 9 to 11 weeks before departure, with average prices around $969. The cheapest single day to book is about 75 days out at $963, while booking much earlier or later can push fares above $1,000.", "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": "There are no nonstop red-eye flights from Denver to Lisbon, but several one-stop overnight itineraries are available where the long leg is a red-eye. For example, you can connect via Newark (UA, departing 8:25 PM and arriving 8:20 AM), via Montreal (AC, 9:45 PM departure, 9:20 AM arrival), via London Heathrow (BA, 6:40 PM departure, 10:35 AM arrival), via Philadelphia (AA, 9:05 PM departure, 9:05 AM arrival), or via Washington Dulles (UA, 10:25 PM departure, 10:30 AM arrival), among others — all arrivals are in the morning hours.", "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": "There is no nonstop service between Denver and Lisbon. Common one-stop routings include United via Newark or Washington Dulles, Air Canada via Montreal or Toronto, American via Philadelphia, British Airways via London Heathrow, Lufthansa via Munich or Frankfurt, Delta via Boston, and TAP Air Portugal via Boston or New York JFK. United via Newark and Air Canada via Montreal each show about six daily connection options, with United via Dulles and American via Philadelphia around five daily, while other patterns appear less frequently. Per-carrier median fares are not provided for this route, so specific fare estimates are unavailable.", "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 Newark, Amsterdam, Paris, and Frankfurt. Newark offers a domestic first leg with a single transatlantic hop and efficient U.S. connections. Amsterdam and Paris provide smooth transfers within a single terminal or airside, and Frankfurt is a major Star Alliance hub with extensive onward links. All three European hubs allow visa‑free transit for U.S. citizens, keeping total travel time competitive."}, "q10": {"question": "Which months have the best weather for traveling to Lisbon?", "answer": "April to June and September to October offer mild, sunny weather with fewer tourists than the summer peak."}, "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 planned stay, and if you're a U.S. citizen, no visa is needed for stays under 90 days. Carry proof of onward or return travel, a payment method for baggage, and any required vaccination certificates."}, "q12": {"question": "Which airport should I use in Lisbon?", "answer": "Lisbon has only one commercial airport, Humberto Delgado Airport, located about 7 km from the city centre. It serves all flights to the city."}, "q13": {"question": "How do I get to Denver Intl Airport from the city center?", "answer": "The A Line commuter rail (RTD) runs from Denver Union Station downtown to the airport transit center in about 37 minutes, offering the fastest and most popular public transit option. Ride‑share services like Uber and Lyft, as well as taxis, provide door‑to‑door convenience with a typical drive of 35–50 minutes depending on traffic. Several shuttle and shared‑van services also operate, and driving yourself is possible with extensive on‑airport parking, though parking fees can add up for longer trips.", "toolsUsed": ["article_lookup"], "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"}]}, "q14": {"question": "Are there hotels or sleeping facilities at Lisbon airport?", "answer": "Lisbon Airport (LIS) does not have any on-site hotels, capsule hotels, or sleeping pods inside the terminals. Several nearby hotels, such as the Meliá Lisboa Aeroporto and Tryp Lisboa Aeroporto Hotel, are located within walking distance or offer shuttle services. The airport also has a free shuttle bus connecting Terminal 1 and Terminal 2, but it does not serve hotels.", "toolsUsed": ["article_lookup"], "references": [{"url": "https://www.sleepinginairports.net/guides/lisbon-airport-guide.htm", "title": "Lisbon Airport Guide (LIS) - Sleeping in Airports", "favicon": "https://www.sleepinginairports.net/nitropack_static/oBWrHkPujHTPIaVWqdDSDhClXUyrYhhb/assets/images/optimized/rev-b853180/www.sleepinginairports.net/wp-content/uploads/2018/09/cropped-sia-logo-180x180.png", "time_published": "2018-09-02T00:00:05Z"}, {"url": "https://www.sleepinginairports.net/hotels/lisbon-airport-hotels.htm", "title": "Lisbon Airport Guide (LIS) - Sleeping in Airports", "time_published": "2026-04-13T18:11:40Z"}, {"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_facilities.html", "title": "Lisbon Portela Airport (LIS) Facilities, Info: Services at Airports in Lisbon Area, Portugal", "time_published": "2016-03-03T00:00:00Z"}, {"url": "https://en.wikipedia.org/wiki/Lisbon_Airport", "title": "Lisbon Airport", "favicon": "https://en.wikipedia.org/static/apple-touch/wikipedia.png", "time_published": "2026-07-20T16:51:21Z"}, {"url": "https://en.wikipedia.org/wiki/Lisbon%20Airport", "title": "Lisbon Airport", "time_published": "2026-04-30T23:41:16Z"}]}, "q17": {"question": "What aircraft are typically used on flights from Denver to Lisbon?", "answer": "There is no nonstop service between Denver and Lisbon. On connecting itineraries the long-haul leg is most often operated by a Boeing 777-300ER (via Toronto), a Boeing 787-10 (via Newark), or an Airbus A350-1000 (via London Heathrow); other widebody types such as the Boeing 787-9, Boeing 777, Airbus A350-900, and Airbus A380-800 also appear on this route. The exact aircraft varies by airline and day, but the Boeing 777 and 787 families along with the Airbus A350 are the most common widebodies. Wi‑Fi and seatback entertainment are widely available on these long‑haul aircraft, though the specific amenities depend on the 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"]}, "q20": {"question": "What are the best airport lounge options when departing from Denver?", "answer": "Denver International Airport has two main lounge options: the Centurion Lounge in Concourse C and the Delta Sky Club in the Main Terminal, Concourse A. The Centurion Lounge offers complimentary premium food, cocktails, and Wi-Fi, with access for American Express Platinum and Centurion cardholders. The Delta Sky Club provides a relaxing space with flight monitors, beer and wine, and printers, accessible to Delta One or SkyTeam business-class passengers, elite members, and certain credit card holders. Both lounges are well-regarded, but note that DEN does not have dedicated United Club or American Admirals Club lounges.", "toolsUsed": ["article_lookup"], "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&regionId=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 rules differ by airline and fare class. Basic economy often excludes checked luggage, while standard international economy typically includes one checked bag and a carry‑on. Premium cabins provide higher 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, with Premium Economy available on select connecting itineraries."}, "q23": {"question": "Are same‑day changes or standby possible on this route?", "answer": "Policies vary by airline and fare; flexible and premium cabins often allow same‑day changes or standby, while Basic Economy typically does not."}}}}