If you didnt know, missiles are very slow cause the server is overloaded with tons of destroyed towers, planes etc. After regeneration they become fast again
I beat this plane with the Privatized Spy Boat, even the Fighter Eagle spotted me and tries to fight me. I defeat him the the Privatized Spy Boat but he also do Pretty Fatal Damage to my Boat So it Concludes that you can beat Fighter Eagle with the Privatized Spy Boat but, you have to be Unspotted by Fighter Eagle by just Hiding Around in Middle Islands and you might land some hit from far range but it difficult because Fighter Eagle is very fast & agile so you might get little bit closer but dont get too close to Fighter Eagle.