i lost 2728 airplanes but the enemy lost 442.
There are various things you can do to improve your fighter performance.
1) Try to fight at 1:1 odds or better. If the enemy has more planes than you, they will improve their killing ability compared to yours.
2) Make sure your planes are set up with proper range in the air regions you are operating. If an air wing only has half the required range to operate in a particular area, it's going to take a huge hit to mission efficiecny and fight worse.
3) Exercise air wings before the war to get their XP up.
4) Research air doctrines. Seriously, these are important.
5) Choose the light aircraft designer before researching the 1940 and 1944 fighter. It boosts agility, a key stat for fighters attacking other fighters.
6) Pick up the 1940 light fighter in a timely fashion and produce it ASAP once you complete research on it. 1940 light fighter is much better than the 1936 fighter.
7) When adding XP to light fighters, I'd focus on engine upgrades, some gun upgrades, and enough reliability to put the plane at 50-60% reliability. More experienced players can run lower reliability planes, but newer players should stick to 50+.
8) If you are Britain, appoint Sholto Douglas to the general staff.
9) If you are Britain or the US, grab the NFs that cut the production cost of light fighters. You'll thank me later.
10) Make sure your planes are operating for airfields that are not overstacked, that they have supply, and that you have enough fuel.