New performance reports from airlines suggest that jetliners in the U.S. flew more full last month than in any other April.

And the early results from April, which indicate that more than 80 percent of U.S. airlines' seats were filled with paying passengers, portend a record-setting — and uncomfortably crowded — summer travel season ahead.

Seven airlines that have reported for April all show fuller planes. No. 4 Northwest ran fullest at 84.9 percent. No. 1 American filled 81.7 percent of its seats. No. 5 Continental filled 82.9 percent. No. 3 Delta, despite a dispute with pilots over cost cuts that included threats of a strike or shutdown in mid-April, filled 77.6 percent of its seats. Even discounters Southwest and AirTran, which usually report load factors lower than the big network carriers, came close to filling 80 percent of their April seats.

This means flights on the most popular routes at the most convenient times were likely to be full. Lou DeLuco, a sale representative from Scottsdale, Ariz., said the crowded conditions lately have landed him more frequently "in the back of the plane or in the dreaded middle seat."

For all of 2005, the domestic airline industry filled 77.6 percent of its seats, according to the Air Transport Association. The April numbers are good news for an industry that has lost more than $40 billion over the last five years. Better yet for the industry, travelers have been paying on average about 13 percent more for their tickets than last summer.

But ATA chief economist John Heimlich said in the group's 2006 outlook statement in January that despite big price increases since last summer, "passenger revenue is about $25 billion per year below where it ought to be, based on the historical relationship between spending on air travel and the nation's economy."

The industry's flying capacity is expected to shrink about 2 percent this year, but consumers are already feeling the squeeze.

Frequent-flier Kathy Brousseau, a data warehouse consultant from Lexington, S.C., says it's difficult to get seats and "to get them at a reasonable cost," because Delta has reduced the number of flights to nearby Columbia, S.C., and downsized its service there to regional jets. "The flights are full and generally overbooked."

Flying in coach is "like being in a two-seat convertible with eight people to begin with," says Glenn Floyd, a human resources executive from Vancouver, Wash. Now, with planes so full, "creature comforts suffer" and boarding and in-flight service are much slower. And, he says, "It seems the patience of the flight crews has been depleted."