Summary: I spent a decade blaming my back. The actual explanation took about thirty seconds once someone finally gave it to me, and it had two halves that nobody puts together.
1

Your Weight Doesn't Spread Evenly

Pressure concentrated at the base of the pelvis when seated

When you sit, almost all of your weight lands on one small area at the base of your pelvis.

That's true for everyone, in any chair. What changes is what's underneath it.

2

Economy Seats Aren't Padded Anymore

Cross section of a modern thin economy seat

Airlines have been stripping the cushioning out of economy for years. Less weight, more seats.

What's left is a couple of centimetres of foam over a hard frame.

3

Your Own Padding Thins With Age

Illustration of natural cushioning thinning over time

This is the half nobody mentions. The natural cushioning on your backside gets thinner over time.

It happens so slowly you never notice.

4

Less On You, Less Under You

Less padding on you and less padding under you

Either one on its own you'd barely notice. Together, your whole weight presses into the thinnest part of you for the entire flight.

At forty you'd land stiff. At sixty you lose the first days of your holiday to it.

"It was never my back. It was two layers of padding disappearing at the same time."
5

The Pressure Keeps Building

Pressure increasing over the hours of a long flight

That's why the end of a long flight is so much worse than the start. It's also why foam cushions let you down: foam crushes flat under constant weight, and then there's nothing left doing the job.

In one study, memory foam came second worst of everything tested. Only the bare seat scored worse. Here's what builds up instead:

  • Buttock & Hip Pain
  • Lower Back Pain
  • Poor Circulation
  • Constant Shifting Fatigue
  • Numbness & Tingling
  • Muscle Strain
  • Dead Legs on Landing
  • Leg & Knee Pain
6

Air Can't Collapse

36 sealed air cells of the Cushy Bum cushion

Cushy Bum is a travel cushion made of sealed air cells. When you sit on it, the air moves between the cells, so your weight spreads across the whole seat and no single point carries everything.

Because it's air, it can't crush flat. The end of the flight feels like the start, and the built in pump lets you set the firmness yourself.

7

Both Kinds of Padding, Put Back

Cushy Bum air cell travel cushion on an economy seat

That's all the Cushy Bum does. It gives you back the padding you lost and the padding the airline took away.

I used mine on a 14 hour flight to Tokyo. No pain at all, I actually slept, and instead of wasting two days recovering I was exploring from the moment I arrived.

Business class upgrade $3,000+
Medical seat cushion (that stays home) $400
Single physio session after a bad flight $150
Cushy Bum — works on every flight, forever Under $100