How to Book When You Don't Know When You Want to Fly

— -- Planning a trip with scattered family members or friends, or do you need to fly to a daughter's side to help with a newborn baby? Or maybe you're simply looking for a nice escape but for one reason or another can't nail down the dates.

Uncertainty is the bane of air travelers; a little hesitation when shopping for plane tickets can cost you hundreds of dollars extra in fees and penalties. Don't lose hope! There are ways around these hurdles.

The Problem: The main obstacle facing those with uncertain dates is the dreaded change fee. This can cost as much as $200 per ticket (American, Delta and United) and even more on international flights. If you book a flight but have to change dates later, you may be stuck with this fee, plus any difference in the fare if the ticket price goes up.

The Scenario: You find a good deal to the family reunion city or there's a great price to your daughter's city where she's about to have the first grandchild. The big unknown is, when to go. So what to do? Four possible solutions.

Solution #1: The 24-hour purchase rule may help. Go ahead and buy tickets if you think everyone can agree on firm travel dates within 24 hours. A Department of Transportation rule requires airlines to provide a day-long grace period so people can change their minds without incurring a penalty.

Note: American works this a little differently from the other U.S. carriers; it allows shoppers to hold tickets for 24 hours (as opposed to a purchase/refund transaction). You claim seats for a particular flight at a specific price and get a day to reconsider without paying the change fee.

Solution #2: Lock in the fare. As far as we can tell, Continental Airlines was the first airline to offer this optional fee-based service in 2010; after it merged with United, the latter co-opted with the FareLock program. FareLock is pretty simple: If you want to keep a fare you found beyond the first 24 hours, pay a fee that starts at $7 or $8 (depending on the route) and United will hold the price for three days or pay a little more and the airline will hold it for a week. This could be useful for those uncertain travel dates and also for gamblers hoping cheaper flights will suddenly materialize (it happens).

The idea of FareLock is catching on; last week, American recently introduced a similar option called Extended Hold which follows the same pattern but allows shoppers to put purchases on hold for three, five or seven days (from $7.99 to $11.99).

Note to shoppers: Fees for the fare-hold services of both American and United are non-refundable.

Solution #3: Southwest Airlines. Travelers with uncertain itineraries can book flights on Southwest with peace of mind because the airline has no change fee (and it is the only major U.S. carrier that can make this claim).