With tar balls on beaches alarming tourism officials in Key West, Fla., and volcanic ash disrupting flights in Europe, this year's summer travel season is off to a chaotic start. Still, "staycations" have gotten old. More Americans were expected to hit the skies this Memorial Day weekend -- the traditional launch of the summer holiday season -- than any year since pre-recession 2007. Here's what to expect, with tips for avoiding chaos of your own.

Planes fill, prices rise

More people will fly, according to the Air Transport Association. But airlines have added few flights since last summer.

Among recession-battered airlines, "there is no rush to return too much capacity into the system," transport association spokesman David Castelveter said.

More travelers and few seats mean airfares are creeping up. Fuel prices also have airlines nervous.

So when should you buy your ticket? The rule of thumb, Castelveter says, is to buy early or face higher prices when planes get near being filled.

But if your departure date is flexible, you might wait, hoping airlines will discount seats at the last minute if a particular flight hasn't filled.

Insurance? Be careful

The eruption of the Eyjafjallajokul volcano in Iceland -- which grounded about 10 million travelers earlier this spring -- has prompted more travelers to buy trip insurance. Beware, though. Consumer group Which? found that some travel agents were overselling insurance without adequately explaining the terms.

Mark Kahler of budgettravel.about.com advises getting a real person on the phone before buying insurance for an upcoming trip. "Pester the person selling it to you," he said. "Make sure you know what is covered."

Don't miss your flight

If you're connecting to a second flight, book stopovers that are about two hours long in case your first flight is delayed, says Kate Hanni of Coalition for Passengers' Rights, Health and Safety.

Check flight status. Go to your airline's website for alerts. You can also sign up with flightstats.com for alerts sent to your iPhone or BlackBerry.