Flight not found from AirlineFlightSchedules API

FlightAware AeroAPI
1

API: https://flightxml.flightaware.com/json/FlightXML2/AirlineFlightSchedules
Request param: {“startDate”:1619726342,“endDate”:1619819942,“flightno”:“5102”,“airline”:“PAL”}
Response: {“next_offset”:-1,“data”:}}

When i searched this flight from Flightaware.com I get it. Here is the screenshot:
Link: https://flightaware.com/live/flight/PAL5102
Screenshot: Flight-aware — ImgBB

May i know, Why we didn’t have it while calling AirlineFlightSchedules API call?

2

It appears they have the schedule listed as PAL102, but are sometimes appending additional numbers to the flights. For example, PAL102 operated as such on April 27, 2021 but then flew as PAL5102 on April 29, 2021. We do not have a schedule that matches the PAL5102 flight, which is why you would not have seen returns.