Investing.com -- Wells Fargo downgraded Hexcel Corp (NYSE: HXL ) and Howmet Aerospace Inc to Equal Weight as it turned more cautious on the aerospace sector, citing the risk of a global economic slowdown affecting both new aircraft production and aftermarket sales.

The brokerage said it cut estimates across the group, projecting a 5-10% average decline in earnings per share.

“We think a global economic slowdown hits both OE and aftermarket,” it said.

Wells Fargo said demand for aircraft could fall by about 300 basis points in a modest slowdown, translating to a 6% impact on aftermarket and a 10% hit to original equipment sales. While it expects airline fleet retirements to pick up “given an old in-service fleet, although don’t think airlines are in a rush to refresh fleets at $60 oil.”

Hexcel was downgraded despite its relative valuation, as the firm said the Airbus A350 program appears to be “struggling to increase rate,” and that Hexcel’s high operating leverage makes it vulnerable if production slows.

Howmet’s downgrade reflects its high valuation and strong stock performance. Wells Fargo said continued earnings beats “may be more difficult to achieve in a slowing economic growth environment.”

The firm maintained a preference for aftermarket-focused names such as General Electric (NYSE: GE ), TransDigm, and RTX, which it said are better positioned in a slower-growth scenario due to pricing power and lower sensitivity to fleet decisions.