UPDATE 1-Airbus insider probe snarls another executive

(Adds details)

PARIS, July 11 (Reuters) - Magistrates investigating alleged insider trading at European defence and aerospace group EADS (EAD.PA) and its Airbus unit on Friday placed another executive under formal investigation while releasing him on bail.

Andreas Sperl, the former financial director of Airbus, was placed under formal investigation after he had been held for questioning for two days, the Paris prosecutor's office said.

Sperl, a German national, is currently head of an EADS plant at Dresden in Germany and is the first person still working for EADS, the parent company of Airbus, to have been put under investigation.

He has to pay a bail of 200,000 euros ($315,400). There is no interdiction against his meeting other people involved in the case, which means he can assume his functions pending the outcome of the investigation.

Former officials Noel Forgeard, Gustav Humbert and Jean-Paul Gut are also under formal investigation, which in France is a step short of charges but can lead to trial.

French police are investigating claims that EADS top executives and industrial shareholders knew of the increasing threat of delays to the Airbus A380 superjumbo when they sold shares in 2005 and 2006.

The announcement of worsening delays in building the world's largest airliner wiped a quarter off the value of EADS shares on a single day in June 2006.

A total of 17 current and former executives, along with EADS shareholders Lagardere (LAGA.PA) and Daimler (DAIGn.DE), were cited in a recent report to prosecutors on suspected insider trading by France's market watchdog AMF.

They have denied wrongdoing. (Reporting by Thierry Leveque; Writing by Swaha Pattanaik; Editing by Quentin Bryar)