03/06/2015 10:56 am ET Updated May 06, 2015

Just How Old Is That Plane You're Flying On?

The world's airlines are buying lots of shiny new planes of all sizes and types, and that's good news for travelers, giving them some sense of justice now that airfares are going up and airlines are raking in profits. Even so, the skies are full of old clunkers -- DC-9s, 717s, early versions of the 757 and 767 and 737, to name a few.

The venerable 757, no longer produced, debuted in 1981, which means that there are some examples plying the airways that could be over 30 years old. Not that older planes are unsafe just because they're old, far from it.

But for those who prefer flying in a newer plane when booking or want to know more about their "ride," just how do you tell an aircraft's age?

Before you book or while at the airport, look up the flight number on There you can find the "tail numbers" (also known as the N-numbers, because U.S.-registered planes begin with an "N," or registration numbers) of any U.S.-registered aircraft. Then you can find out the plane's age at the FAA Registry page by entering the N-number here.

On some planes, the registration number is displayed on placards inside the plane, either in the cockpit or near the doors or jump seats. Or if you can see it from the terminal or the tarmac, the N-number is displayed near the tail on the plane's fuselage.

If you prefer something less airline-geeky and quantitative, here are some visual ways to tell if the plane you're flying on is no spring chicken.

The flight attendant call button icon is wearing a skirt or it's labeled "stewardess."

There's an ashtray on the seats' armrest.

There's a razor blade disposal slot in the lav.

There are video monitors hanging down from the ceiling instead of in the seatbacks.

There's a no smoking sign above the seats rather than a "turn off electronics" symbol.

The in-seat power outlets are DC instead of 110-Volt (granted, some newer aircraft have no in-seat power ports at all).

There's a stairway to the outside in the tail (like that Delta MD-88 that almost landed in the East River on Thursday).

There are three engines instead of two or four (e.g., the 727).

The company that made it no longer makes commercial airliners (e.g., Lockheed).

The economy class seat padding is more like a La-Z-Boy than a church pew ("slimline seats").

There's a landing gear over the tail instead of at the front (e.g., a DC-3).

There's no landing gear. But you'd be flying in a Pan Am Flying Boat. And you'd be time traveling.