NEW YORK — Hundreds of passengers who were stranded on parked JetBlue planes for up to 10 1/2 hours could have been evacuated sooner if the airline had not waited to ask airport officials for help, the company founder said Thursday.

The airline acknowledged that it hesitated nearly five hours before calling in shuttle buses to unload 10 jets that spent the day sitting on runways at Kennedy Airport because of icy weather and gate congestion.

While they waited, exasperated passengers sat within sight of the terminal without food, adequate restrooms or a reasonable explanation as to why they were not moving.

JetBlue officials finally phoned the Port Authority of New York and New Jersey, which runs area airports, at 3 p.m. to ask for staircases and buses to get people off the planes and back to the terminal.

"We should have called them sooner," said JetBlue founder and CEO David Neeleman.

Once they did, some passengers were free within 30 minutes. Others had to wait while the Port Authority shoveled out snow-covered equipment and rounded up drivers.

Many of the stranded passengers did not return to the terminal until 6 p.m. Most had boarded their aircraft around 8 a.m. Some of the jets were incoming flights that had been on the ground since 10 a.m. Six flights were stranded for more than eight hours.

Neeleman said he could not apologize enough.

"We should have done better," he said. "There was an opportunity to do better."

JetBlue's problems began developing when snow and ice pellets made takeoffs difficult but did not stop landings, Neeleman said, resulting in the airline accumulating 52 airplanes at a terminal with 21 gates.

Neeleman said the airline held out too long for a break in the icy conditions, then had planes "freeze to the ground" where they had been waiting.

Some passengers spent an hour or two on delayed flights before being brought back to the terminal. Others saw their flights canceled.

Weather delays of up to six hours continued to plague JFK on Thursday. More than 300 flights were canceled. At Newark Liberty International Airport in New Jersey and LaGuardia Airport, delays averaged more than two hours.

Terminals at JFK filled with passengers trying to arrange alternative flights. JetBlue canceled 195 of its 568 planned flights in an attempt to avoid being overwhelmed for a second straight day.

Other airlines experienced problems, too. Mark Mannix, a government affairs officer for New York's Metro-North Railroad, said he spent hours stranded aboard an American Airlines jet.

The plane was scheduled to depart for Miami at 5:45 a.m. It did not push back from the gate until nearly 7:45 a.m. and soon halted for another delay. The pilot finally returned to the terminal at 10:45 a.m. after deciding it was not safe to fly.