Light trucks and SUVs continued to remain high on many shopping lists.
Nissan and Fiat-Chrysler recorded slight sales gains in May, while Ford, Toyota, Honda, Volkswagen and General Motors posted declines.
Automakers were hampered by two fewer selling days in May, supplies that did not meet demand and natural disasters in Japan. But the mood remained generally optimistic at the start of the hot summer selling season.
"It's easy to look at May's sales and conclude that the retail car market is losing steam, but it's too soon to say for sure that auto sales are leveling off," said Edmunds.com Director of Industry Analysis Jessica Caldwell. "As in previous years, the summer months will flush out more incentives from automakers, and the urgency that shoppers show in responding to these incentives will give the industry a much better sense of how the market is trending."
"Notwithstanding a challenging calendar, we managed to muscle our way to our strongest May sales in over 10 years," said Reid Bigland, Fiat-Chrysler senior vice president of sales in a statement. "Initial sales of our all-new Chrysler Pacifica minivan are brisk and we expect further sales growth from this vehicle over the next few months as dealer inventory continues to build."
Sales at General Motors were down 18 percent compared to the previous May.
"The demand has been so strong for our new launch products, there's no question we could've sold more; however, production was impacted at Fairfax, Lordstown and Spring Hill by the Japanese earthquakes," said Kurt McNeil, GM vice president of sales operations, in a statement. "Current dealer inventories for launch products are about half of what we'd like for launch products, but availability is improving, which sets us up well for the second half of the year."
"Customers are showing how much they value the fuel economy, towing capability and technology we offer in our trucks with F-Series sales producing another strong gain in May," said Mark LaNeve, Ford vice president of U.S. marketing, sales and service, in a statement.
Toyota reported sales of 219,339 units, a decrease of 9.6 percent from May 2015.
"Industry sales remain steady in May with the shift toward light trucks and SUVs continuing," said Bill Fay, Toyota division group vice president and general manager, in a statement. "Mirroring that trend, Toyota division SUVs had a best-ever month, led by RAV4, Highlander and 4Runner."
Volkswagen Group of America sales tumbled 17 percent compared to May 2015, as the German automaker continued to grapple with the diesel-emissions crisis.
However, the Volkswagen Tiguan compact SUV produced the best May results on record with 4,394 vehicles delivered, a 43 percent increase over May 2015.
Honda reported May sales of 147,108 units, a year-over-year decline of 4.8 percent, but said the company remains on track for a second straight year of record-setting sales.
"We continue to see solid demand for Honda cars and light trucks, and all indicators point to a strong summer selling season for Honda," said Jeff Conrad, senior vice president and general manager of the Honda Division, in a statement. "With our balanced lineup and an all-new Ridgeline pickup and restyled and re-engineered 2017 Accord Hybrid launching this summer, we remain bullish on our prospects for a third consecutive yearly sales record for the Honda brand."
Hyundai touted "another record-setting May sales month with 71,007 units," in a tweet. Details were not immediately available.
Edmunds says: The May sales report may be just a bump in the road, as automakers expect better outcomes in June as inventories and incentives build.