The ME-109 was the standard by which all other fighters of WWII were judged. It served the Luftwaffe in almost every capacity, from interceptor to night-fighter to ground attack and photo reconnaissance. The ME-109 was produced in greater numbers than any other plane (approximately 30,000) and remained in use by some countries until 1967. The G (Gustav) version was the result of the need to upgrade the 109 series to better combat the newer Allied fighters appearing over the skies of Europe. The ME-109G included better armament and more horsepower than the previous E versions.

The ME-109G was armed with two MG 131 13mm cowl mounted machine guns and either an MG151 20mm or Mk 108 30mm cannon firing through the spinner. It could also be armed with 50 pound or 250 pound bombs, 20 or 30mm underwing cannons, or external drop tanks to extend the notoriously short range of the ME-109 fighter series.

The Gustav was eventually fitted with the Daimler-Benz DB605 series engine, the most powerful engine to be fitted to the 109s. The DB605 was an inverted Vee, 12 cylinder liquid cooled engine producing 1,475 horsepower at takeoff. This gave the Gustav a top speed of 386 MPH.

In the hands of an experienced pilot the Gustav was a formidable weapon. Many of the top scoring aces of Germany got most of their kills flying the ME-109. As the war continued, however, the shortcomings of the series showed up, such as difficult takeoff and landing traits that in the hands of less skilled pilots proved sometimes fatal. Most later modifications to the 109 series were attempts to tame these shortcomings, but the Gustav was still flown in combat right up to the end of the war.