Quick way of looking up details by faFlightID

I have over 100,000 flights I recorded a month ago and I want to collect some additional details on the flights. I collected the flight data using SearchBirdseyeInFlight over a 24 hour period.

I now need updated departure time, arrival time, seat capacity, and tail number for those flightids. I found a couple requests that do it, one is slow the other is quick.
Is there a way to get all this data in one request (per faFlightID? Or in bulk?)

Also sometimes it doesn’t return any results. Example:

flightxml.flightaware.com/json/F … 1435276800
Takes a long time and finds nothing, but other flight ids work, just not all of them.
{“AirlineFlightSchedulesResult”:{“next_offset”:-1,“data”:]}}

flightxml.flightaware.com/json/F … edule-0029
Quick and finds something
{“AirlineFlightInfoResult”:{“faFlightID”:“VRD752-1435117500-schedule-0029”,“ident”:“VRD752”,“codeshares”:“CAL9650”],“tailnumber”:“N639VA”,“meal_service”:“”,“gate_orig”:“”,“gate_dest”:“B1”,“terminal_orig”:“2”,“terminal_dest”:“”,“bag_claim”:“”,“seats_cabin_first”:8,“seats_cabin_business”:0,“seats_cabin_coach”:141}}

That is currently the best way to do so using FlightXML.

Ok thanks. Would you be able to explain why that query above returns no data for a flight that definitely exists? Just wondering if my query parameters are wrong.