Tbh I legit always wear cargo shorts/trousers for flights. Benefit is twofold, first you can carry quite a lot of shit this way, secondly the lower pockets are way more accessible sitting down on an aircraft.
Is this jacket or a shirt/dress? If it’s a jacket, You can take it off and put it through x-rays. If it’s a shirt/dress, I’m not sure of the consequences of walking through security naked or in your underwear…
I haven't been to an airport with in years where only one person at a time can unload their stuff into the x-ray machine, usually they have spots for five or six persons.