How old is the aeroplane you are flying on?

The US and most of the developed world have superb standards and maintenance regulations, the result of decades of experience that have made the system incredibly safe, Aboulafia said.

It’s also important to remember that a plane may be 20 years old, but its engines and other major systems could have been recently manufactured or upgraded, said Todd Curtis, a former airline safety analyst with Boeing and the founder of AirSafe.com.

There’s less pressure on the airlines to upgrade the interior, unless it’s a safety issue or a redesign that will save money.

Last week, Delta announced it will spend $1 billion through mid-2013 to improve the planes it already owns, rather than invest in new aircraft.

The upgrades will include adding in-seat audio and video on demand in economy class on dozens of planes and installing full flat-bed seats in BusinessElite on 90 trans-oceanic aircraft.

For many air travellers, the noises a plane makes can be interpreted as a disturbing sign of its age.

“There’s a strange whistling in the cabin,” wrote a poster recently on Flightsfromhell.com, recalling a tense journey on what appeared to be an old plane.

“The engines sounded like they were at full throttle the whole trip... (and) the whole plane made a horrible ‘crunching’ sound on touch-down.”

Flexible machine

The aircraft then “limped up to the gate creaking like a haunted mansion. Nothing specifically bad happened on the flight, but we were all pale and shaking once we got off,” the poster wrote.

Curtis, who has been around airplanes most of his adult life, said he’s also sensitive to unusual noises while flying, but explained that most creaks and squeaks air travellers worry about are routine.

“Every aircraft, even brand new, is designed to be somewhat flexible — it’s not a piece of rock. It’s a flexible machine that’s designed to bend ever so slightly under certain kinds of stresses.
So you might have structural creaking going on because parts of the fuselage or the wings are flexing during flight,” Curtis said.

“You could also have equipment inside the aircraft, for example, the furnishings, the overhead bins, the seats, which could have the creaky, squeaky stuff going on.”

Shaken down

Which means that even the new Boeing Dreamliner likely won’t be immune to making noises. Some travellers may also not be eager to fly it right away precisely because it’s new.