Documents
Naval test pilot school notes (Gallagher, Higgins, Khinoo, Pierce)

Fixed wing performance theory

Drag theory (Dragbusters)

Aircraft performance flight testing  (WM Olson)

Aircraft model development   (D Scholz, 2 parts)

Aircraft performance (Airbus Industry)

Airplane flight dynamics and automatic flight control (J Roskam, Part I)

Jet Transport performance methods (Boeing Industry)
Links
Some links to aerodynamics sites and documents. Topics presented are of general interest, more or less advanced. Understanding the information they contain may require some skills. Also, some interesting course notes, exercices, software and java applets.
Beginner's Guide to Aerodynamics (NASA)

Aerodynamics for Students (Auld & Srinivas)

See How It Flies (JS Denker)

Aerodynamics for Students (University of Sydney)

Applied Aerodynamics Links (M Selig, a huge collection of links)

Aircraft Flight Dynamics (RF Stengel lecture, Princeton University)

Flightlab Course Notes

Ed Williams's aviation page (Aviation formulary and other documents)
Aerodynamics