Germanwings
Germanwings was founded in 1997 and is wholly owned by Lufthansa. It started its low cost services on October 27th, 2002. Later it was integrated into Eurowings (another Lufthansa owned company) and their 4U code disappeared in March 2018. Further on it only flew in wetlease for Eurowings. It ceased service on April 7th, 2020.