The Me 262 Schwalbe ("Swallow") was the world's first operational jet-powered fighter aircraft. In combat, when properly flown, it proved to be essentially untouchable, able to outrun its Allied counterparts by as much as 100 mph. The Me 262 claimed a total of 509 Allied kills against the loss of about 100 Me 262s. As the only aircraft in Luftwaffe service able to operate safely at that point in the war, the design was pressed into a variety of roles, including light bomber, reconnaissance and even experimental night fighter versions. The Me 262 is considered to have been the most advanced German aviation design in operational use during World War II and according to some Allied historians it was an aircraft that, had it entered service just two years earlier than it did, might have won air supremacy back for the Luftwaffe. The Allies countered its potential effectiveness in the air by relentlessly attacking the aircraft on the ground, or while they were taking off or landing. Maintenance during the deteriorating war situation and a lack of fuel also reduced the effectiveness of the aircraft as a fighting force. In the end, the Me 262 had a negligible impact on the course of the war due to its late introduction and the small numbers that were deployed in operational service. The Me 262 influenced the designs of post-war aircraft such as the North American F-86 and Boeing B-47.