Flight Deals from Athens to Chicago O Hare Airport from $358

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. 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.

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. For this route, fares for the requested travel direction were unavailable, so the pattern shown is derived from the reverse direction, which shares the same seasonal demand cycle.

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. Cheapest prices are determined by finding the lowest fare Priceline users have found for the requested route and date 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.

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.

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.

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.

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. 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.

Methodology

The cheapest day of the week and time of day to depart are drawn from the same large sample of real fares Priceline users found on this route in the last 72 hours, grouped by the day of the week and by the time-of-day window of the outbound departure, with the lowest and average price reported for each.

Methodology

The typical price, the lowest fare, a 'great deal' threshold, and how fares are spread across price bands are summarized from a large sample of the real fares Priceline users found on this route in the last 72 hours, with a small fraction of extreme outlier fares excluded from the range.