Japanese air bag component maker Daicel Corp. and Britain's biggest defense firm, BAE Systems, are designing an air bag for military helicopters that they hope to sell to the U.S. Army, according to three sources with knowledge of the proposal.

The two companies will finalize a design in the coming months and then present a prototype to the U.S. Army, which, if interested, will ask for a formal proposal, according to one of the sources, who declined to be identified because he was not authorized to speak to the media.

After the U.S. Army, they would offer the air bags to the Japanese Self-Defense Forces and eventually to commercial customers, the source said.