topdeutsche (also known as simply top.com, and with its official name being Transport Organisation fur Passagierluftverkehr) is a defunct German low cost carrier. At the end of its operation, it operated a fleet of Boeing aircraft (mostly of the 737 type) from its main base in Dusseldorf, along with its other bases. The airline would specialise in connecting German cities with other European cities, focusing mostly on underserved city-pairs. As such, it would offer a cheaper alternative for business travellers.

The airline would be founded in March of 2006 by its CEO. By September of that year, topdeutsche would already have its certification, and contracts for several aircraft. Later that year, 4 737-300s would be delivered under lease agreements. Just a few days later, on January 14th, the airline would issue a press release where it would reveal its first services, which included the following destinations: Milano, Praha, Torino, Wien, Warszawa. Later that year, on the 17th of May 2007, topdeutsche would operate its inaugural flight, TD100 from Düsseldorf, using D-ADBN, a former DBA 737-300. By the same week, all five inaugural destinations would be flown to, and load factors would tend to sit around the high 60s.

Shortly after, topdeutsche would announce that 3 new routes from Dusseldorf would be joining its flying programme by early September: Munich, London-Gatwick, and Rome-Fiumicino. Interestingly enough, plans for a new base in Nuremberg would also be announced, as Brussels would also be jo9ning the airline's flight programme.