Daiseycutter, I'd be inclined to take some specialist advice re: drugs to prevent malaria, because of the reasons listed. The literature I've looked at states that larium (chemical name = mefloquine) is contra-indicated in "those performing precision activities, eg pilots" but my reference is rather outdated (1997). It sounds like ausdoc has sight of more up to date literature.
On one hand, you want to take medicines safely, and only if needed, on the other, you want to prevent malaria contraction. (about 2000 cases in the UK per year, resulting in 6-10 deaths).
Remember, if you cut down the number of bites, you cut down the risk. Bite avoidance is most important from dawn to dusk, so wear liong sleeves and pants after dusk.
Mosquito nets soaked in permethrin may help, in less protected accomodation. The "plug in" coils may also help.
Our local school of tropical medicine recommends using a repellant containing DEET (diethyl-toluamide). Spays, gels lotions are usually available, and I believe one of our local chemists sells impregnated wrist bands.
Good luck, if you hear of any up to date research re: flying and larium, post a message, I'd be interested to see it.