After WWI, the struggling aircraft industry survived mainly by modernizing obsolescent airplanes. De Havilland-designed wooden DH-4 biplanes were rebuilt using the Boeing-developed arc welding process for steel-tube fuselages. These aircraft were designated DH-4M (for modernized). Boeing rebuilt a total of 298 DH-4s in all versions between 1920 and 1925. Fokker American's Atlantic Aircraft Corp. rebuilt many of the aircraft which were designated DH-4M-2s.