LOS ANGELES — The tiny sport plane Roy Halladay was flying when he fatally crashed into the Gulf of Mexico was made for entry-level pilots like him, though the plane’s chief designer and test pilot died while flying one earlier this year, officials and experts said.

Halladay, the 40-year-old former Blue Jays and Phillies pitcher, had been the proud owner for less than a month of his ICON A5, and was among the first to fly it, with only about 20 in existence, according the website for ICON Aviation.

In one of many enthusiastic tweets about the plane, Halladay said it felt “like flying a fighter jet.”

Rolled out in 2014, the A5 is an amphibious aircraft meant to be treated like an ATV, a piece of weekend recreational gear with folding wings that can easily be towed on a trailer to a lake where it can take off from the water.

“The way that a lot of people described it is a Jet Ski with wings,” Stephen Pope, editor-in-chief of Flying magazine, told The Associated Press. “It’s really a play thing.”

The man who led the plane’s design, 55-year-old John Murray Karkow, died while flying an A5 over California’s Lake Berryessa on May 8, in a crash the National Transportation Safety Board blamed on pilot error. The NTSB also will investigate Halladay’s crash to determine the cause.

In other tweets, Halladay said he had dreamed about owning one of the planes, and said in video on the company’s website that he had to talk his wife into letting him get one. The son of a corporate pilot, Halladay had been forbidden to take up aviation until he retired from baseball at the end of 2013.

Pope said “the plane itself is great,” but he had concerns about Halladay, a new pilot with little flying time, taking the craft out over water at low altitude, though the plane was marketed as a craft that could do that.

“They still think that that’s the way the airplane should be flown, and there are people in aviation who completely disagree with that,” Pope said. “They think you should not have a low-time pilot flying low over water. That’s a recipe for disaster.”