Now the Transportation Security Administration is coming under fire to do something about it - in Philadelphia, and at other airports as well.
At a number of airports across the country, passengers are finding incredibly long lines at TSA checkpoints.
PHOTOS: TSA delays at PHL and other airports
Recent video from LAX shows wait times of one, two, even three hours.
"I don't know if they don't have enough people, or the people aren't interested in working hard enough," said Barbara Edwards of Dover, Delaware.
"This time the lines were really, really long," said Jermaine Pitts of Burlington Twp., N.J.
RAW VIDEO: Long lines at Philadelphia International
Passengers are not the only ones complaining.
A spokesman for American Airlines says the lines at TSA checkpoints have become unacceptable.
He says almost 6800 passengers missed their flights between March 14 and March 20.
He says the worst airports include Philadelphia International, Atlanta, L.A., Miami and Dallas.
"I think that honestly they're understaffed," said Pitts.
The TSA says the truth is, they've seen a decrease in the number of screeners nationwide due to budget cuts.
This, at a time when Congress is demanding tighter security measures due to recent terrorist acts.
Currently there are only 41,000 screeners, the lowest in 5 years.
With summer coming, the TSA is trying to add just under 200 new screeners a week to bring levels up to the Congressional cap of 42,500.
But even then, TSA Administrator Peter Neffenger is warning passengers to be prepared for delays.
"I think you can expect to see some longer wait lines," he said, "simply because of the number of people moving."
Given that, the best advice may be to sign up for TSA Pre-check, the agency's version of a Fast Pass. But be aware, there is a fee to do so.
Your only other alternative, experts say, is to show up even earlier for your flight than you normally would.