Greetings
First of all, let's remember,
"Countries have NO permanent friends or permanent enemies,
Only permanent self-interests"
Thus, during the WW2, the US and China were allies against the Japanese. Barely 6 years later, the US and Japan were allies against China, ie , during the Korean War
Another interesting question," could a few F-18s given to a country be enough to make a it become a major world power?"
Hardly the "Big Boys" are already playing with new generation toys like molecular nanotechnology, laser, EMG, GAMMA, etc and yeah, SPACE, don't forget space weapons. "The country that controls the high ground in Space, will be the dominant military power"
In general, a few F-18s , SU-30s, KILOs, SAVA cruisers, aircraft-carriers don't frighten anybody,but stuff like molecular nanoteechnology would, a superpower make. That separates the Men from the boys