United Cuts Staff, Parks Planes

Northwest will remove 15 to 20 aircraft from service -- two this month and the rest in the fall. Come September, Northwest will reduce domestic system capacity by 5 percent versus its 2008 business plan, the carrier announced in April.

US Airways has announced it will get rid of six planes, a 2 percent to 4 percent reduction in capacity, in the second half of 2008. US Airways said that does not affect any employees.

Continental is removing 14 planes from service starting this fall. Like other carriers, including United, the airline is retiring older, less fuel-efficient planes. That translates to a 5 percent reduction in domestic, mainline capacity. The carrier hasn't announced any employee layoffs.

Related

Why Airlines Might Abandon Your City

WATCH: Airlines Struggle to Stay Afloat

WATCH: Airline Fuel Crisis

American announced earlier this month that it plans to retire 40 to 45 mainline aircraft and 35 to 40 regional jets, reducing capacity by 11 percent to 12 percent.

Starting in September, American is discontinuing its Chicago to Buenos Aires, Argentina, service, eliminating its Boston to San Diego service, and scaling back its service from Chicago to Honolulu. In January of next year, the carrier will stop flying from Chicago to Honolulu altogether. This September, the carrier is also restructuring American and American Eagle flights out of San Juan, Puerto Rico, to the United States and various Caribbean destinations.

Indeed, cuts are affecting travelers in cities of all sizes around the country. According to the Department of Transportation Statistics, scheduled commercial service has disappeared entirely this year from 37 small airports around the country.

And several aviation experts agree that there's more to come.

"Unless the fuel bubble implodes, and I don't think it will, we're going to see whole cities losing service," said Field, editor of Airline Business Magazine. "We're going to see, probably, another airline bankruptcy or two."

Meantime, Field said the slew of cutbacks is going to continue making things difficult for travelers.

"It means we're going to have to search a lot harder to find deals," he said. "There will be deals, but they're going to be harder to find. You're going have to spend more time on your computer."

"I think if there's any good news on the horizon, I think we'll see less delays in the future because we have fewer planes in the air," said aviation economist Darryl Jenkins. "All the planes will still be packed full of passengers."

ABC News' Randy Gyllenhaal contributed to this report.