The P-38 AKA "Lightning" (aka Fork-Tailed Devil) was produced by Lockheed. During WW-II, Lockheed produced a series of newsletters called Hangar Flying filled with tips and humorous cartoons. I've got the complete collection of the Hangar Flying newsletters, and as time allows, I intend to put them all up here. I find them very informative, along with funny, and very well written, with just a slight bit of sexism (but what did you expect from WW-II pilots?). These pages are graphic heavy, running close to a meg a page, but I felt the illustrations are worth it - most of the illustrations are by Dick Shaw.

Issue 1 - Take Offs Issue 5 - Dive Characteristics. Issue 9 - Compressibility.
Issue 2 - Normal Flight. Issue 6 - Maneuvers. Issue 10 - Limitations, etc.
Issue 3 - Single Engine Flight. Issue 7 - Engineering. Issue 11 - Ground Check.
Issue 4 - Landing. Issue 8 - Self-hypnotism.

Other P-38 Links:

P-38 Online - Really nice site, covering the P-38 from the prototype stage (XP-38, YP-38), to the most recent production models (P-38J, P-38M (2-seater night fighter), etc). Lot's of tech info, Pilot profiles, Theatres of action, Plane Specs, Scenarios, etc.