Well, I have no idea what ENY stands for but a planes ENY value determines how much perks u get for killing other players. Your ENY value is divided by the value of the guy u killed and the quotient of that will be how many perks u get. So for example if a 109g10 with an ENY of 20 was killed by a p40 with an ENY of 40 it will be 20/40=2 so the p40 will earn 2 perk points. Now if the 109 got the p40 then it'll be 40/20 which'll add up to some decimal number and the 109 will earn that number of perks.
Same goes for OBJ which works like ENY but acts against objects not players. Examples of objects are hangars, town buildings, convoy trucks, etc.