The six aircraft companies mentioned in the crossword solutions are CESSNA, BOEING, AIRBUS, Saab, STOL, and PLANES. CESSNA is an American aircraft manufacturer founded in 1927 that produces single-engine aircrafts. BOEING is an American aerospace company founded in 1916 that produces commercial airplanes, defense, space, and security systems. AIRBUS is a European aerospace company founded in 1970 that produces commercial airplanes, helicopters, and satellites. Saab is a Swedish aerospace and defense company founded in 1937 that produces military aircrafts and missiles. STOL stands for Short Takeoff and Landing and is a type of aircraft that can take off and land in a short distance. Aero is a Russian aircraft manufacturer founded in 1992 that produces light aircrafts. PLANES is an American aircraft manufacturer founded in 1946 that produces light aircrafts.