Wide leg trousers are not recommended on flights, more so on long haul! They will drag on the floor of piss in the toilets, you’re be trying the hoist the bottoms up to stop it while hovering over the loo. Just dont.
The joggers with a cuff are perfect, dark so they don’t show any spills (i still think back to the one poster ages ago who recommended a crisp white cotton shirt to fly in 🥴😆) elastic waistband for bloating, not too thick material or to thin, sometimes the A/C on flights can be cold or way stuff and hot.
Wear trainers and take thick socks to put on while seated, I take cheap throw away hotel slippers to use when going to the bathroom- never go barefoot 🤢 or in socks.
Top wise, the most comfortable bra and pants you own, and layers - a t-shirt and sweatshirt etc, a pashmina is good as pillow, blanket etc.
Over ear noise cancelling headphones (Bose are good)and a good eye mask.
In addition I always take a lip balm and a hydrating face mist - stop you touching your face but gives a blast of hydration when needed.