9 best things to do at an airport when waiting out a flight delay

If you're traveling international and have some foreign currency left over, try heading to a duty-free store — or items bought in a country without tax.

While you always save money on taxes, prices for certain goods vary by airport and country, according to the price comparison website Duty Free Addict. Yet for items with high taxes outside the airport — like alcohol and tobacco — duty-free could be a good bet.

Some airports offer their own large selection of duty-free products you can't get in the country. If you were looking for a deal on French perfume, for instance, Paris' Charles de Gaulle Airport has good deals on Chanel, Hermès, and other high-end scents you can take with you in bottles over the 3.4-ounce requirement, according to The Points Guy.

If your flight was delayed and the airline is at fault, you may qualify for compensation.

While weather delays or issues with air traffic control won't get you cash, losing your luggage or waiting on the tarmac for over three hours means you're entitled to some compensation from the airline.

The app AirHelp tracks flight delays and sees if there are ways to get you compensation. The service gets compensation for as much as $700, and helps both domestic and international passengers.

If you're delayed as a result of an airline issue, you can see if they will give you a pass to the airport lounge.

Lounges are often more comfortable than other seated areas around the airport, plus offer free food and drinks. If you're going to be at the airport an extra couple of hours, you may as well be comfortable.

Airlines won't be immediately inclined to give you a pass, however, so Skyskanner recommends asking nicely.

Lifehacker writer Heather Yamada-Hosley said a flight layover offers time to catch up on work.

Her suggestions include:

• Sorting through work emails in the airport so you can save time during your first day back from vacation.
• Prepare your customs forms before you land.
• Write a travel blog documenting your adventures while the memories are still fresh.

If in case you locked away toys and other supplies in your luggage, many of the major airports in the US are kid friendly. Here are some of the best airports for children, according to to the blog Family Vacation Critic.

• Chicago O'Hare International has 24/7 mothers rooms where you can nurse or relax with infants, plus an entrance to The Children's Museum of Chicago's play area.
• The Baltimore/Washington International Thurgood Marshall Airport has a children's play area with the option of exploring parts of a real plane.
• Dulles International Airport has an aviation-themed play area developed by NASA. Kids can enjoy interactive games, slides, and educational games regarding air and space travel.
• Miami International Airport can help your child or other passengers with special needs prepare for their flight in a controlled, safe environment. The program, called MIAair, is a "dress rehearsal" for the real flight that was developed in part by the University of Miami-Nova Southeastern University Center for Autism.

While this might only take a few minutes during your potentially long flight delay, filling up your water bottle after having to dump it out in security will save you money.

Airports notoriously hike up prices for bottled water — sometimes as much as $5 for a bottle you can get for less than a buck at the gas station.

Plus, Business Insider's Caralynn Lippo said she fills up her bottle so she doesn't get dehydrated in the air and "have to ask for 45 of those tiny cups of water the flight attendants give you." Since air travel dehydrates your body and skin, make water your friend at the airport.

Paying for airport WiFi can be a rip-off, says Smarter Travel. So if you have the option of paying for WiFi or using your time to unplug, choose the latter.

That being said, if you have emails to catch up on, there are hacks to get past the paywall. Smarter Travel recommends going to an airport Starbucks, which typically offers its own WiFi, or seeing if you can sit near a lounge that may have its own connection. Thrillist, meanwhile, says you can sometimes find WiFi passwords on Foursquare threads.

You're going to be on a flight sitting down for however many hours, so why not make good use of the time you get to walk around?

If you tire of taking laps around the airport, or don't want to veer too far from your gate, here are some exercises you should consider:

• Do lunges on the moving walkway: "The people mover that makes it easy to traverse miles of airport terminal space can also be an effective substitute for a track or treadmill," Health Magazine says. "Just make sure you don't run into anybody."
• Wall sits: "No seats available? No problem! Sit up against a wall with your legs at a 90 degree angle and hold it for as long as you can," Skyscanner says.
• Carry your luggage instead of rolling it: "For an extra challenge — and an unexpected core workout — carry your luggage by the handle, making sure to keep your body tall and straight," WebMD recommends.

Plus, some airports — like Baltimore-Washington International Airport and San Francisco International — offer their own gyms and fitness centers if you want a more intense workout. The Points Guy has a full list of airports with gyms.