Clara Nguyen

Lockheed Martin’s F-35 program has drawn thousands of reader remarks on Aviation Week since the aircraft reached initial service. The most pointed thread this week grew out of a comment by retired Marine officer Don Bacon. He noted that “150 to 160 modifications” sit between many early-build jets and the Block 3F standard that the U.S. services need for combat. His remark sparked fresh debate about concurrency, spiraling costs, and schedule risk.

The F-35 promised reach without rival, yet its heart – Pratt & Whitney’s F135 – burns fuel like an older design. Thrust-specific fuel consumption (TSFC) shows why. The F100-PW-229 that powers late-model F-15s and F-16s clocks 0.726 lb/hr/lb. The F135 sits at 0.889 lb/hr/lb, a 22 percent penalty that drags range and keeps tankers busy.