Boeing has an airline performance engineer training document called "Jet Transport Performance Methods" (or very similar). Doc ref is D6-1420 if my recollection is correct. My copy is at work so I am not able to check just now.
Aimed at undergraduate engineer level in terms of difficulty but an excellent standard reference work.
Keep in mind that several of the standard undergrad aerodynamics texts cover theoretical performance pretty well. For practical implementation, the Boeing doc is real fine.