I know right?
Hot wash all your clothes after every wear, including jeans and jumpers. Remember that if you're going to be around people in the evening (for example, on an evening flight), that after washing off the offensive funk of a few hours' existence, you should change into a fresh set of clothes — one single clean set of clothes per day may not be enough. Don't forget that if you're not lucky enough to live in a mansion, drying clothes inside might make them smell of cooking or mustiness, so you'll probably need to dry all this clothing outdoors or use a tumble dryer. And make sure to do extra-thorough rinsing to avoid any scent from your detergent. Wash your coat regularly and make sure you haven't walked past a smoker or cooked anywhere near it since you last washed it.
Showering/bathing every night isn't good enough, because then you'll have night sweat (ew) on you all day, so you must wash in the morning too/instead (as well as a second time, if you're going to be around people later in the day too), even if that's inconvenient for you. Whatever your hair type, you must wash it frequently. Brush your teeth and gargle at regular intervals throughout the day, lest people detect the smell of plaque on your breath.
And when you go on holiday, have a shower at 3am before your early morning flight out (and brush your hair in case someone can smell the tousle), and for your evening flight home, make sure to find somewhere to have a strip wash and a full change of fresh clothes immediately before travelling. (Even if your hotel checkout was at 10am, and your luggage space is limited).
Bugger that — I haven't got the time, energy, money, skin resilience, or inclination to spend hours every day washing jeans and jumpers that have been worn for a couple of hours, or making sure I'm never around people unless it's less than 8 hours since I last fully decontaminated my body. Nah… if I get on an early morning flight after a bath (plus antiperspirant etc., obviously) the night before and clean clothes that morning, or an evening flight having had a shower that morning, and the person next to me really can smell me for the first minute or so until their nose habituates — oh well. Never mind. There's probably something about them I can detect and don't much like, too.
We've all got a responsibility to do what we reasonably can to get along with others. That includes making sensible efforts to avoid being disruptively noisy, smelly, or otherwise offensive, but also being tolerant of moderate or unavoidable noise, smells and disruption from other people too.