ATLANTA (CNN) -- Major airlines were busy over the Memorial Day weekend -- but predictions of more travelers than ever flying last Friday fell short of expectations.

Last week, the Air Transport Association predicted that travelers gearing up for the Memorial Day weekend would make Friday, May 22, the busiest travel day in aviation history, with more than two million people expected to fly. That expectation was based on advanced airline ticket bookings.

However, the major airlines, represented by ATA, said the association's prediction didn't live up to expectations.

ATA also predicted load factors -- the percentage of seats filled on a flight -- would be as high as 83 percent system-wide.

ATA told CNN it does not follow up on its predictions with statistics on the numbers of people who actually flew. ATA spokeswoman Diana Kronin said the association publishes air travel predictions as a service to travelers to help them plan trips during busy holiday travel periods.

Despite falling short of breaking records, the airlines did report heavy travel volume. Delta Air Lines was 1,000 passengers short of breaking its all-time travel record, which remains the Sunday after Thanksgiving in 1996. Delta spokesman Bill Barry said the airline flew 357,887 passengers on last Friday, representing a load factor of 85 percent.

United Airlines said passenger loads did not break records, although it was the busiest Memorial Day weekend ever for the carrier. United spokesman Joe Hopkins said the airline flew about 280,000 passengers, or an 81.7 percent load.

American Airlines said the number of passengers traveling on its planes on Friday was below record levels and represented only an 80 percent load.

The number of passengers traveling last Friday didn't break records at US Airways either. Spokesman Dave Castleveter said Friday was the heaviest travel day of the Memorial Day weekend, with loads close to 90 percent, but that's not a record for the airline. The Sunday following Thanksgiving last year was the carrier's busiest travel day ever.