I would like to propose the air spawn be removed for aircraft not under the designation Light Bomber, Hydroplane, Frontline Bomber, and Long Range Bomber. This would be removing the air spawn for all aircraft except for dedicated level bombers. The reasoning behind this is simple: the air spawn of aircraft like the Ju87, Do 335, SB2C, A36, and others like them allow these planes to act as faux interceptors. Strike aircraft of these type would be fine to have spawn at the airfield (or forward airfield) since they have virtually no reason to climb to bomber height to accomplish their intended roles. It would also be beneficial, since they are usually slower than their fighter counterparts, that they would arrive to bases/ground targets while the fighters are already occupied with each other instead of fighters trying to intercept the air spawned strikers since they are the closest target.
Edit: With interceptors and Air Defense Fighters almost all having climb rates above around 2500 ft/min. I would like to amend this suggestion to include interceptors and air defense fighters to also lose their air spawn. They have the climb rate necessary to accomplish their task by design. The only Interceptor/ADF I saw with below around 2500 ft/min are the J1N1, Ki-108 Kai, Ki-61-I, Potez, Do-217, and the Ju-88 C-6. They are almost all rank 2 aircraft or below, so their weak performance is somewhat expected. This will have similar effects to strike aircraft losing their airspawn, but with minimal effects as the rank 3+ interceptors/adf have comparable climb rates to the fighters they share a battle rating.
I will use the Do 335 B-2 and B24D-25-CO as a comparison to why these strike aircraft do not need an air spawn when compared to level-bomber aircraft.
The B-24 is a 5.7 Long Range Bomber that has a climb rate of 907 ft/min unloaded (spaded). I would like to note that the B-24 cannot be taken out without some sort of payload, so it will never reach the 907 ft/min climb rate. Unloaded, it would take 15+ minutes to reach 14,600 feet, which is where it currently spawns. It can carry a maximum payload of 4372 kg, which reduces that climb rate by 572 ft/min to new climb rate of 335 ft/min. A climb rate of 335 ft/min would mean that climbing to the spawn altitude would take around 45 minutes of flight.
The Do 335 B-2 is a 5.7 strike aircraft that has a climb rate of 1998 ft/min unloaded (spaded). It can be taken out without payload, so it can reach this climb rate under normal conditions. Unloaded, it would take less than 2 minutes to reach 3200 ft, where it currently spawns. It can carry a max payload of 1000kg, which reduces that climb rate by 708 to a new climb rate of 1290 ft/min. A climb rate of 1290 ft/min means climbing to the spawn altitude would take less than 3 minutes.
As you can see, the Do 335 would be minimally impacted by the change to an airfield spawn. But the aircraft that would be impacted the most by this spawn change would be the Bombers that play these aircraft. The Do 335 is always played as a faux interceptor because it spawns at speed and has a great climb rate for a strike aircraft. This is the case for almost all of the strike aircraft. Jet strikers at rank 5 have even better climb rates than propeller driven aircraft, so this problem is made worse at rank 5. Comparing the B-29 with the Me 262 A-1a/U1 at 7.3 is an even more unbalanced comparison and just shows that the strike aircraft have no need for an air spawn. If this change was made, all bomber aircraft at all ranks would benefit. They would have to worry about dedicated Air Defense Fighters/Interceptors and Fighters climbing to intercept instead of a ground strike aircraft that spawns in the air. This change will make aircraft like the B-17s, Lancasters, B-29, Tu-4, Me-264, He-177, and more actually viable to play and accomplish their primary purpose in Air RB.