Loss of flying hours under the budget cuts has increasingly led Air Force pilots to reject lucrative re-enlistment bonuses to take jobs with the civilian airlines, acting Air Force Secretary Eric Fanning said Thursday.

"Pilots aren't taking them," Fanning said of the incentive bonuses that range from $25,000 to a maximum of $250,000.

Fanning did not give figures on the number of pilots who have rejected the bonuses but said "pilots want to fly," and there was less opportunity for doing that with whole squadrons periodically being grounded to save money. Absent help from Congress on funding, "we're going to have to continue these rolling groundings for squadrons," Fanning said.

In addition, airline jobs are opening up as more airline pilots retire, Fanning said at an issues forum sponsored by Defense One.

"It's not just compensation that keeps people in the military, it's the mission," Fanning said. Addressing the growth rate of compensation was a key factor in meeting the requirements of the sequester process under the Budget Control Act.

Personnel costs now make up about 40 percent of the Air Force budget, about 50 percent of the budgets of the other services and "we're looking at 60 percent" overall in coming years unless the Defense Department acts to limit pay raises, Fanning said.

"We're not cutting compensation, we're just slowing its growth," said Fanning, who added that rising costs for TRICARE will also have to be trimmed.

The growth in spending for the military on TRICARE was "unsustainable," Fanning said, and failing to deal with it would result in the Air Force having to cancel replacements for aging aircraft. "If we don't address it, we will have aging platforms. That will have a worse effect on morale" than the rolling groundings of squadrons, Fanning said.

Overall, Fanning said, "morale is really as bad as I've seen it on the civilian side and the uniformed side. But it is better than you think it is, and better than we deserve it to be, because we've got an amazing mission."