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Fli provides comprehensive filtering options to help you find exactly the flights you need. All filters can be combined to create highly targeted searches.

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Cabin class

Filter flights by cabin class using the SeatType enum: 
from fli.models import SeatType, FlightSearchFilters, PassengerInfo, FlightSegment, Airport

filters = FlightSearchFilters(
    passenger_info=PassengerInfo(adults=1),
    flight_segments=[
        FlightSegment(
            departure_airport=[[Airport.JFK, 0]],
            arrival_airport=[[Airport.LAX, 0]],
            travel_date="2026-04-15"
        )
    ],
    seat_type=SeatType.BUSINESS  # Filter for business class
)

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Available cabin classes

  • SeatType.ECONOMY - Economy class (default)
  • SeatType.PREMIUM_ECONOMY - Premium economy
  • SeatType.BUSINESS - Business class
  • SeatType.FIRST - First class

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Stops

Control the maximum number of stops using the MaxStops enum: 
from fli.models import MaxStops

filters = FlightSearchFilters(
    # ... other parameters
    stops=MaxStops.NON_STOP  # Only direct flights
)

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Available stop options

  • MaxStops.ANY - Any number of stops (default)
  • MaxStops.NON_STOP - Direct flights only
  • MaxStops.ONE_STOP_OR_FEWER - Maximum one stop
  • MaxStops.TWO_OR_FEWER_STOPS - Maximum two stops
The MaxStops enum uses internal values (0-3) but provides descriptive names for clarity.

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Airlines

Restrict results to specific airlines by passing a list of Airline enums: 
from fli.models import Airline

filters = FlightSearchFilters(
    # ... other parameters
    airlines=[Airline.BA, Airline.VS]  # British Airways and Virgin Atlantic only
)

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Common airline codes

  • Airline.AA - American Airlines
  • Airline.BA - British Airways
  • Airline.DL - Delta Air Lines
  • Airline.UA - United Airlines
  • Airline.AF - Air France
  • Airline.LH - Lufthansa
  • Airline.VS - Virgin Atlantic
  • Airline.AC - Air Canada
  • Airline.JL - Japan Airlines
  • Airline.QF - Qantas
See the Airline enum for the complete list of supported airlines.
The airlines filter only includes flights operated by the specified carriers. Codeshare flights may not appear in results.

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Time windows

Restrict departure and arrival times using TimeRestrictions. All times are in hours from midnight (0-23) in local time: 
from fli.models import TimeRestrictions

filters = FlightSearchFilters(
    # ... other parameters
    flight_segments=[
        FlightSegment(
            departure_airport=[[Airport.JFK, 0]],
            arrival_airport=[[Airport.LAX, 0]],
            travel_date="2026-04-15",
            time_restrictions=TimeRestrictions(
                earliest_departure=6,   # 6:00 AM
                latest_departure=10,     # 10:00 AM
                earliest_arrival=12,     # 12:00 PM
                latest_arrival=18        # 6:00 PM
            )
        )
    ]
)

​
Time restriction parameters

  • earliest_departure - Earliest departure time (0-23)
  • latest_departure - Latest departure time (0-23)
  • earliest_arrival - Earliest arrival time (0-23)
  • latest_arrival - Latest arrival time (0-23)
All parameters are optional. You can specify only departure times, only arrival times, or any combination. 
from datetime import datetime, timedelta
from fli.models import (
    Airport,
    FlightSearchFilters,
    FlightSegment,
    PassengerInfo,
    TimeRestrictions,
)
from fli.search import SearchFlights

filters = FlightSearchFilters(
    passenger_info=PassengerInfo(adults=1),
    flight_segments=[
        FlightSegment(
            departure_airport=[[Airport.JFK, 0]],
            arrival_airport=[[Airport.LAX, 0]],
            travel_date=(datetime.now() + timedelta(days=30)).strftime("%Y-%m-%d"),
            time_restrictions=TimeRestrictions(
                earliest_departure=6,  # 6 AM
                latest_departure=10,   # 10 AM
                earliest_arrival=12,   # 12 PM
                latest_arrival=18,     # 6 PM
            ),
        )
    ],
)

search = SearchFlights()
results = search.search(filters)

​
Sorting

Sort flight results using the SortBy enum: 
from fli.models import SortBy

filters = FlightSearchFilters(
    # ... other parameters
    sort_by=SortBy.CHEAPEST  # Sort by lowest price
)

​
Available sorting options

  • SortBy.NONE - Default Google Flights sorting (default)
  • SortBy.TOP_FLIGHTS - Google’s recommended flights
  • SortBy.CHEAPEST - Lowest price first
  • SortBy.DEPARTURE_TIME - Earliest departure first
  • SortBy.ARRIVAL_TIME - Earliest arrival first
  • SortBy.DURATION - Shortest duration first
The TOP_FLIGHTS option uses Google’s algorithm to balance price, duration, and convenience.

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Advanced filtering

​
Duration limits

Set a maximum total flight duration in minutes: 
filters = FlightSearchFilters(
    # ... other parameters
    max_duration=720  # Maximum 12 hours (720 minutes)
)

​
Layover restrictions

Control layover airports and maximum layover duration: 
from fli.models import LayoverRestrictions

filters = FlightSearchFilters(
    # ... other parameters
    layover_restrictions=LayoverRestrictions(
        airports=[Airport.BOS, Airport.ORD],  # Prefer these layover airports
        max_duration=180  # Maximum 3-hour layover (in minutes)
    )
)

​
Price limits

Set a maximum price for flights: 
from fli.models import PriceLimit, Currency

filters = FlightSearchFilters(
    # ... other parameters
    price_limit=PriceLimit(
        max_price=500,
        currency=Currency.USD
    )
)
Currently only USD is supported for price limits.

​
Combining filters

All filters can be combined for highly specific searches: 
from datetime import datetime, timedelta
from fli.models import (
    Airline,
    Airport,
    FlightSearchFilters,
    FlightSegment,
    LayoverRestrictions,
    MaxStops,
    PassengerInfo,
    SeatType,
    TimeRestrictions,
    SortBy,
)
from fli.search import SearchFlights

filters = FlightSearchFilters(
    passenger_info=PassengerInfo(adults=2, children=1, infants_on_lap=1),
    flight_segments=[
        FlightSegment(
            departure_airport=[[Airport.JFK, 0]],
            arrival_airport=[[Airport.LHR, 0]],
            travel_date=(datetime.now() + timedelta(days=30)).strftime("%Y-%m-%d"),
            time_restrictions=TimeRestrictions(
                earliest_departure=8,
                latest_departure=14
            )
        )
    ],
    seat_type=SeatType.BUSINESS,
    stops=MaxStops.ONE_STOP_OR_FEWER,
    airlines=[Airline.BA, Airline.VS],
    max_duration=720,
    layover_restrictions=LayoverRestrictions(
        airports=[Airport.BOS, Airport.ORD],
        max_duration=180
    ),
    sort_by=SortBy.CHEAPEST
)

search = SearchFlights()
results = search.search(filters)

​
Filter validation

Fli uses Pydantic models to validate all filter parameters. Invalid values will raise a ValidationError: 
from pydantic import ValidationError

try:
    filters = FlightSearchFilters(
        passenger_info=PassengerInfo(adults=1),
        flight_segments=[
            FlightSegment(
                departure_airport=[[Airport.JFK, 0]],
                arrival_airport=[[Airport.JFK, 0]],  # Same as departure!
                travel_date="2026-04-15"
            )
        ]
    )
except ValidationError as e:
    print(e)  # "Departure and arrival airports must be different"
Common validation errors include:
  • Same departure and arrival airports
  • Travel dates in the past
  • Invalid time ranges (earliest > latest)
  • Missing required fields

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