There are a lot of new faces at the top of the aerospace and defense industry, with a half-dozen CEOs named recently and a seventh appointment imminent.

The new class of leaders includes Wes Bush of Northrop Grumman Corp., Scott Donnelly of Textron Inc., Jay Johnson of General Dynamics Corp., Tim Mahoney of Honeywell International Inc.'s aerospace unit and Dennis Muilenburg of Boeing Co.'s Integrated Defense Systems. And Walt Havenstein left his job as CEO of BAE Systems plc.šs North American unit to become CEO of Science Applications International Corp. last month, creating an opening that BAE is expected to fill by the end of the year.

The (relatively) young turks are Muilenburg, Bush and Donnelly, who are all replacing longtime CEOs in their 60s. Muilenburg, 45, was recently tapped to run Boeing's defense business when Jim Albaugh was shifted to the company's troubled Commercial Airplanes unit. Bush, 48, will succeed retiring Northrop Grumman CEO Ron Sugar on Jan. 1, having been groomed for the top job with a succession of increasingly important management posts. And the 47-year-old Donnelly will take over at Textron -- the parent of Cessna Aircraft Co. and Bell Helicopter -- on Dec. 1, succeeding retiring CEO Lewis Campbell.

General Dynamics took a different succession route in selecting Johnson to replace longtime CEO Nick Chabraja, who is retiring. At 62, Johnson is only four years younger than Chabraja, a sign that the company wanted more time to groom its rising stars. Johnson, a former U.S. chief of naval operations, has sat on General Dynamics board since 2003. He left his job as CEO of Dominion Virginia Power to join the company last year.

Maloney, 53, was abruptly elevated to Honeywell's top aerospace post last month after CEO Rob Gillette was lured by solar module manufacturer First Solar Inc. Maloney has more than 30 years' experience in the aerospace industry, including 18 years at United Technology Corp.'s Sikorsky Aircraft. He was Honeywell Aerospacešs chief technology officer before his recent promotion.

While the new CEOs are a diverse bunch, they face the common challenge of figuring out how to keep growing sales and profits in a tough environment. Commercial aerospace is mired in a downturn. U.S. defense spending is leveling out and may decline after eight years of robust increases. For this new class of leaders, the test starts now.

Image credit: Northrop Grumman