What to wear on a long flight that is neither jeans nor tracksuit bottoms

Jeans are stiff and cold, tracksuit bottoms look like you have given up, and the gap between them is narrower than it should be. What holds up.

The trousers
Soft, dark, matte, with a waistband that is not rigid. A wool or wool-blend trouser with a slight stretch is the best of both. Failing that, a dark twill with a bit of give. The single detail that matters most is the waistband, because you swell on a long flight and a hard button becomes genuinely unpleasant somewhere over the ocean.

Layers, because the cabin is not one temperature
A t-shirt, a light merino or fine-knit layer over it, and something with a front opening you can take off without disturbing anyone. Merino specifically, because you will wear it for twenty hours and arrive not smelling of it.

Shoes
Slip-on or very easy to unlace, because they come off at security and should come off in the air too. Half a size of room, since feet swell. Avoid anything you would not want to walk a terminal in.

Small things that matter more than they should

• No hard seams or rivets where you sit.
• Pockets that close, because things migrate out of open ones in a reclined seat.
• Something with a hood or a scarf, which doubles as a pillow and blocks light.
• Nothing new. A flight is the worst possible place to find out something rubs.

The principle: dress as though you might have to look presentable on arrival, and be comfortable enough to sleep. Those are compatible; the tracksuit only wins the second one.