Boeing Co is confident that proposed changes to the 787 Dreamliner will provide a permanent solution to battery problems that grounded its newest jet, a senior executive said on Monday.

The U.S. planemaker has also made significant progress in pulling together a plan to launch a revamped version of its best-selling 777 wide-body jet, Boeing Commercial Airplanes marketing vice president Randy Tinseth told a conference of aviation financiers.

Based on a mixed bag of industry indicators, Boeing sees continued strength in the aircraft market despite uncertainty over the world economy, Tinseth told the International Society of Transport Aircraft Trading.

Regulators grounded the 50 Dreamliners in use by airlines globally in mid-January after lithium-ion batteries burned on two planes.

Tinseth said the company's proposed 787 solution, which is being evaluated by U.S. regulators, is a "permanent fix" for the plane's problems. "It is a solution that we believe provides three levels of protection for the airplane and it's a solution that we're confident will ensure safe and reliable service for the 787 in the future," he said.

Tinseth said new-plane demand was coming from developing economies such as China, southeast Asia and Latin America. He also noted strong replacement demand for airplanes in the United States, Europe and Russia, and said the spread of low-cost carriers was a good sign for aircraft purchases.