ATA Airlines late last night announced it was ceasing operations immediately, stranding passengers holding tickets on its 15 daily flights from Hawaii to the West Coast.

The Indianapolis-based carrier had filed for Chapter 11 bankruptcy protection earlier yesterday.

ATA's Hawaii routes were to Los Angeles, Oakland, Phoenix and Las Vegas.

Although the company said it was canceling flights as of 10 p.m. Hawaii time, its Flight 4586 to Phoenix was scheduled to leave with passengers at 12:10 a.m. today, following a two-hour departure delay.

That was expected to be ATA's last flight out of Hawaii.

The sudden shutdown came two days after Aloha Airlines' final flight and left ticket-holding ATA passengers with the same difficult options: scramble to get a seat on another airline, and seek refunds if purchased by credit card or through the bankruptcy court if ATA tickets were purchased with cash.

The company issued a statement last night saying it could not stay in business after losing a key contract for military charter flights.

ATA, founded in 1973, employed about 2,230 workers and was operating 29 aircraft at the time of its shutdown. It claimed to serve 10,000 passengers daily.

It had seven daily flights out of Honolulu, five from Maui, and one each from Kona, Hilo and Lihue. It has about 50 employees in Honolulu.

The airline was no longer flying as of 4 a.m. Eastern time, a recording on 800-435-9282 (I Fly ATA) said last night.

Shayrah Akers, 25, of Sacramento, Calif., was stuck at Hono-lulu International Airport last night after she could not get a standby seat to Phoenix.

"The economy's just going crazy," Akers said of the two airline shutdowns. She and friend Kelcey Hamilton of Kapolei were on a cell phone last night trying to get a flight before giving up.

Akers appeared to be the only stranded ATA passenger at the airport last night, but more will join her as they discover today their flights have been canceled.

The company last night issued this statement on its Web site:

"After filing for Chapter 11 on April 2, 2008 in the U.S. Bankruptcy Court in Indianapolis, IN, ATA Airlines has discontinued all operations and cancelled all current and future flights. Following the loss of a key contract for our military charter business, it became impossible for ATA to continue operations. Unfortunately, we were not in a position to provide our customers or others with advance notice.

"We apologize for the disruption caused by the sudden shutdown of ATA and regret the impact on passengers, employees, suppliers, and other parties. ATA customers should seek alternative arrangements for current and future travel. A list of other airlines serving ATA's destinations is available here.

"ATA customers who purchased tickets using a credit card should contact their credit card company or travel agency directly for information about how to obtain a refund for unused tickets.

"ATA currently is unable to provide refunds to customers who purchased tickets directly from ATA with cash or a check. These customers may be able to obtain a full or partial refund for their unused tickets by submitting a claim in ATA's Chapter 11 proceedings."

ATA said information about submitting a refund claim will be available at www.bmcgroup

.com/ataairlines.

It also said that passengers who purchased tickets from Southwest Airlines for flights operated by ATA should contact Southwest Airlines at 800-308-5037.