The IRS says people who bought airline tickets on or before July 22 for travel beginning July 23 or after, are entitled to a refund on federal taxes, but how easy it will be to get the money back is up in the air.

The refunds are due because Congress let the taxes expire after a budget showdown last weekend effectively shut down the Federal Aviation Administration.

Until things are resolved, airlines can't collect the taxes on tickets sold after July 23, and the government isn't authorized to collect the taxes on tickets sold before that time if people who bought those tickets travel during the shutdown period.

The IRS is asking airlines to handle the refund process, but they aren't required to, and most are directing customers directly to the IRS, which says it is still working on a procedure for handling refunds.

"Because the IRS has no information about passenger ticket purchases or travel dates, travelers who are unable to obtain a refund from the airline will be required to submit proof of taxes paid and travel dates to the IRS under procedures that are under development," the agency said in a question and answer posting at http://www.irs.gov/.

Several types of federal taxes include a 7.5 percent excise tax on tickets expired, but others are still being collected, including fees for passenger security and local airport construction projects.

JetBlue Airways Corp., based in New York, posted a note on its website telling passengers it would provide refunds upon email request for people traveling within the next seven days. It advised customers to check back later if they are traveling after the seven-day period.

American, Virgin America, United, Continental and Southwest were directing customers to the IRS.

Seattle-based Alaska Airlines/Horizon Air posted a note on its website saying it wants to help facilitate the tax refund for customers, and is working on a process to do so. In the meantime, spokeswoman Marianne Lindsey said the airlines are directing people to the IRS.

Most airlines raised fares by the amount of the uncollected taxes, and pocketed the difference, a move that has drawn ire from government officials. The FAA estimated its losses at $30 million a day, most of which is now going to the airlines that have raised fares. Delta Air Lines said it's getting an extra $4 million to $5 million a day.

"They're collecting this money and it's going to their bottom line and I think that is not right," U.S. Transportation Secretary Ray LaHood said at a White House press briefing in Washington. "It's not fair for them to do that, and I made that known to them."

Alaska/Horizon is one of the few airlines that have passed the tax savings onto customers — estimated at $25-$50 per round-trip.

Bookings have been up. Lindsey said the policy of passing the savings on will continue "as long as this goes on."

Virgin America, which competes with Alaska on some routes, is also passing on the tax savings on flights out of Seattle and Mexico.

"Some fares have actually gone down beyond the (tax) discount," said Virgin's Abby Lunardini.