It already is.
Lufthansa has 15 Airbus 380 on order.
Yes. As of July 2013, Lufthansa has 10 Airbus A380-800s, with an order for 7 more.
The service ceiling for an Airbus A380 is 43,000 ft (13,106 metres).
A few of them are: Lufthansa Singapore Airlines Air France Emirates Qantas British Airways
From one of the operating airlines; Emirates, Qantas, Singapore Airlines, Air France, and Lufthansa.
There are four main airlines currently using the Airbus A380, which is the largest passenger airliner in the world. These airlines are Emirates, Singapore Airlines, Qantas, and Lufthansa.
The A380 has a service maximum of 43,000 ft.
advantages of airbus A380
The first Airbus model, the A300, entered service with Air France in May 1974. The most recent model, the A380 "super-jumbo", entered service with Singapore Airlines on 15-Oct-2007.
52 A380's have been delivered or are in service in 2011
The maiden flight of the Airbus A380 was 27-Apr-2005. It entered service with Singapore Airlines on 25-Oct-2007.
As of July 2011 52 are in service.