Monocoque in the context of "Underbone"

The Messerschmitt Bf 109 is a monoplane fighter aircraft that was designed and initially produced by the German aircraft manufacturer Bayerische Flugzeugwerke (BFW). Together with the Focke-Wulf Fw 190, the Bf 109 formed the backbone of the Luftwaffe's fighter force during the Second World War. It was commonly called the Me 109 by Allied aircrew and some German aces/pilots, even though this was not the official model designation.

The Bf 109 was designed by Willy Messerschmitt and Robert Lusser, who worked at BFW during the early to mid-1930s. It was conceived as an interceptor. However, later models were developed to fulfill multiple tasks, serving as bomber escort, fighter-bomber, day-, night-, all-weather fighter, ground-attack aircraft, and aerial reconnaissance aircraft. It was one of the most advanced fighters when it first appeared, being furnished with an all-metal monocoque construction, a closed canopy, retractable landing gear, and powered by a liquid-cooled, inverted-V12 aero engine. First flown on 29 May 1935, the Bf 109 entered operational service during 1937; it first saw combat during the Spanish Civil War.

The Citroën Traction Avant (French pronunciation: [tʁaksjɔnaˈvɑ̃]) is the world's first mass-produced, semi-monocoque bodied, front-wheel drive car. A range of mostly four-door saloons and executive cars, as well as longer wheelbased "Commerciale", and three row seating "Familiale" models, were produced with four- and six-cylinder engines, by French carmaker Citroën from 1934 to 1957. With some 760,000 units built, the Traction Avants were the first front-wheel drives made in such (six-figure) quantity.

Whilst front-wheel drive and four-wheel independent suspension had been established in production cars by Auto Union, and subsequently by others a few years prior – the Traction Avant pioneered integrating these into a mass-production car with a crash resistant, largely unitary, monocoque body. Additionally, the car was also an early adopter of rack and pinion steering.

The Land Rover Freelander is a series of four-wheel-drive vehicles that was manufactured and marketed by Land Rover from 1997 to 2015. The second generation was sold from 2007 to 2015 in North America and the Middle East as the LR2 and in Europe as the Freelander 2. The Freelander was sold in both two-wheel and four-wheel drive versions. The name 'Freelander' is derived from the combination of 'Freedom' and 'Lander'.

After having built exclusively body-on-frame 4WD vehicles for half a century, the first generation Freelander was the brand's first model to use monocoque (unibody) structures, and was offered in three- and five-door body options, including a semi soft-top. The second generation (2007–2015) dropped all two-door options, leaving only a five-door estate car-like body, and – after 62 years – became the brand's first ever to offer a two-wheel drive option (as of 2010).