U.S. airlines were dogged more by anxiety than by operational glitches on Wednesday as the Thanksgiving travel rush began in earnest with scattered delays and no major problems.

The Federal Aviation Administration (FAA) reported mostly smooth operations from coast to coast at the biggest airports, including those notorious for travel headaches like Chicago O'Hare, where United Airlines is based, and John F. Kennedy in New York, which is home to JetBlue and a hub for Delta Air Lines.

Favorable weather throughout much of the country early in the day was the biggest plus for travelers, but worsening conditions pushing east and accelerated traffic volume began causing a few hiccups by afternoon.

The system is working fairly efficiently today. There are no major problems, said FAA spokeswoman Diane Spitaliere.

The 12-day November holiday travel period is the busiest of the year. Airlines expect to carry some 27 million people over the period -- 4 percent more than last year. Wednesday, the day before Thanksgiving, usually brings a travel rush. The real one-day crush is expected on Sunday, when travelers return home.

Delays have worsened this year due to exploding demand and airline over-scheduling at peak times. At times, the aging air traffic control system could not keep pace with the volume of flights.

Airlines were nervous heading into the November period that worsening delays experienced during the summer vacation rush would carry into this week. Worries were especially acute for the New York area, which handles one-third of all commercial traffic.

To ease pressure on the air traffic control network, the U.S. military cleared its coastal air space in the East for airlines from Wednesday to Sunday. Spitaliere said the FAA acquired access to it a few hours earlier than planned.

There is supposed to be some (bad) weather later so it will be particularly useful then, Spitaliere said.

Additionally, air controllers gave traffic priority to bigger airports around New York, creating some back-ups at secondary locations. The FAA also was prepared to slow flights around Boston and other New England states to ensure a smooth traffic flow in New York, if delays mounted in the East.

By mid-afternoon, delays averaged 44 minutes at Boston, nearly an hour at Newark, New Jersey -- where Continental Airlines has a hub -- and more than an hour at New York's LaGuardia, where US Airways has a major presence. At White Plains, New York, delays exceeded two hours.

MINIMAL MELTDOWNS

Service meltdowns at JetBlue and American Airlineslast winter as well as deteriorating performance over the summer tarnished the industry's reputation and prompted government and congressional scrutiny.

We recognize the concern of our customers around these times, and obviously there has been a lot of attention to this holiday in particular, said Megan McCarthy, a spokeswoman for UAL Corp, parent of United Airlines.

In anticipation of higher traffic, airlines beefed up services, staff and flight schedules. Both United and American said they have made every effort to keep delays to a minimum.

Today, we really expect things to go smoothly. We've got everything in place, weather is generally good around the system, AMR spokesman Tim Wagner said.

Airline expert Terry Trippler at www.myvacationpassport.com said carriers were determined to clean up their sullied reputations.

This is the most pro-active I have ever seen airlines going into a holiday season, he said. They are hiring extra baggage handlers, extra ticket counter staffers, extra gate agents. Some even have extra planes and crews, just in case.

(Additional reporting by John Crawley in Washington, editing by Maureen Bavdek)

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