On the first mission of every level take the SU-25 Frogfoot loaded
fully with Maverick missiles. Fly over all the terrain destroying 
every SAM and anti-aircraft site. This makes the following missions
easier and safer. After destroying all the SAM and anti-aircraft 
sites, take the Harrier up with one drop tank and 2 x 2,000lbs bombs.
Watch for any enemy aircraft taking off to locate SPUDD's aircraft 
base. Once located, use the Harrier to destroy the runway. Now the 
SPUDD aircraft are grounded, before you start any missions take a 
fighter plane up, and destroy those in the air. 
This should leave you with total air supremacy enabling you to 
complete the missions unhindered.