What do airlines owe you if you're left stranded by weather, air traffic problems or another emergency that causes your flight to be delayed or canceled?

Here in the United States, not much of anything except a rebooking or refund for a canceled flight.

Hotel rooms? Meals? Cab fare? Strictly at the airlines' discretion. Most will provide a hotel room if a mechanical problem forces an overnight stay, but not when weather interferes. Just ask the thousands who slept in airports after tornadoes in Texas forced American Airlines and American Eagle to cancel 1,900 flights in April.

It's a different story in Europe, where European Commission regulation 261 says that when a flight is delayed or canceled for any reason, airlines must provide meals during waiting times, and assistance with phone calls -- and for cancellations or reroutings that require overnight stays, a hotel and transportation to get to it. The law applies to any airline flying to or from a state in the European Union and any airlines (including U.S. airlines) flying out of Europe.

Some types of delays and cancellations also qualify passengers to claim financial penalties. You'll find information on foreign airline websites. British Airways offers a clear explanation at www.britishairways.com. Scroll to the bottom of the home page and click on "Legal," then on "Flight cancellation and compensation."

No such laws cover airlines flying strictly within the United States or Canada, but one airline -- Air Canada -- has come up with a clever way to spread some goodwill. There's a price, of course, but it's small -- likely enough to cover the airline's cost without leaving travelers feeling dinged.

Air Canada's On My Way program covers passengers whose flights are disrupted for any reason within 48 hours of departure. Severe weather is the usual reason, but it could be anything.

If flights are canceled, passengers get rebooking on the first available flight, even if it's on another airline. If that's not possible, there's the option of free car rental, a benefit to anyone who would rather drive home than wait for the weather to clear.

Meal allowances are provided for delays longer than four hours, and the airline provides hotel rooms for disruptions requiring overnight stays. The details are spelled out at www.aircanada.com.

The On My Way program is good only for flights within North America. The cost is $25 each way for trips up to 1,000 miles and $35 for long-haul travel. Given that most airlines charge that much for checking a bag, this is one fee that seems to offer good value.