General Motors Co (GM.N) and Ford Motor Co (F.N) reported slight dips in U.S. new vehicle sales for April, but GM lifted its outlook for U.S. sales this year based on encouraging signs that the broader economy will grow.

GM now projects the U.S. auto industry will sell between 14 million and 14.5 million cars and trucks this year, up from its previous outlook of 13.5 million to 14 million.

"Over time, strength in the manufacturing sector and strong retail sales will lead to more job creation," GM sales executive Don Johnson said in a statement. "That will help more consumers put the recession behind them."

The sales declines at GM and Ford were due partly to a quirk in the calendar. April has three fewer selling days than last year, which can skew results.

Including medium and heavy trucks, Ford expects the overall industry to post an annual sales rate in the "mid-14 million" range. Chrysler Group LLC, the No. 3 U.S. automaker, forecast an April sales rate for the industry of 14.6 million vehicles.

That would be stronger than the 14.4 million rate projected by economists, according to Thomson Reuters, and would also top the March rate of 14.4 million.

GM reported an 8 percent decline in sales, due a 25 percent drop in fleet sales, to 213,387.

Ford sales fell 5 percent to 180,350 from 189,778 a year earlier. Sales of its Escape SUV model, which is expected to be replaced later this year, fell by a fifth while Fiesta subcompact sales dropped 44 percent.

When adjusted for the fewer selling days, Ford said its April sales rose 7 percent.

Last week, executives said Ford's incentive strategy in April would contribute to a drop in its U.S. market share for the month. TrueCar.com said incentives on Ford cars and trucks fell about 10 percent, compared with a drop of 4.7 percent for the industry.

Chrysler, controlled by Italian automaker Fiat SpA (FIA.MI), said sales rose 20 percent to 141,165 vehicles, compared with 117,225 in the same month last year. Volkswagen AG (VOWG_p.DE) reported a 31.5 percent increase in sales.

Auto sales are watched as one of the earliest snapshots of American consumer demand. In recent months, sales figures have proven a bright spot in an economy that expanded at a 2.2 percent annual rate in the first quarter.

But there are mounting signs that the broader U.S. economy is losing steam. Analysts debate whether high fuel prices and warm weather boosted sales in the first quarter, potentially leading to a pullback in sales later in the year.

Ford shares were up 1 cent at $11.29 and GM shares were up 13 cents at $23.13 on Tuesday morning on the New York Stock Exchange.