Drone maker AeroVironment Inc.’s sales lost altitude last quarter, making investors unhappy with its low-flying performance.

The Monrovia firm, which also makes electric vehicle chargers, last week reported revenue of $47.1 million for its first fiscal quarter ended Aug. 1. That was 9.3 percent lower than the same period the previous year. Overall, AeroVironment saw a net loss of $6.98 million (minus 30 cents a share) for the quarter, which widened by 93 percent from a year earlier.

At 30 cents a share, the loss exceeded analysts’ expectations of a 14 cents-a-share loss. Revenue, too, was below an anticipated $53.9 million. 

The news sent AeroVironment’s stock price into a tailspin Sept. 2, shedding 9 percent to close at $21.26 after the previous day’s earnings release. Shares fell 9 percent in total for the week, making the firm one of the biggest losers on the LABJ Stock Index (See Page 38.)

The shortfall in revenue was largely due to two orders being pushed into the second fiscal quarter and continued weakness in AeroVironment’s electric vehicle-charging products segment, Troy D. Jensen, an analyst for Piper Jaffray & Co. in Minneapolis, wrote in a research note.

The firm’s electric vehicle products still make up a small part of its revenue, bringing in $6.88 million last quarter, down 36 percent from the same period the previous year. By comparison, the firm’s revenue from drone sales dropped by just 2.5 percent to $40.2 million over the same period.

Despite the disappointing quarter, Chief Executive Timothy E. Conver said in a conference call last week that AeroVironment is on track for its annual plan.

“Our core business is strong and we are making meaningful progress across our growth portfolio designed to drive significant stockholder value,” he said during the call.

Jensen also remains optimistic about AeroVironment’s technology and positioning in the emerging unmanned aerial vehicle market.

“The company’s core (unmanned aircraft systems) business continues to see strong demand from domestic customers and is beginning to see growing interest from international allies,” he wrote in his note.

Jensen was encouraged as well by AeroVironment’s addition of commercial drone services and other growth initiatives that are starting to show some traction. But, he added, those growth opportunities won’t contribute meaningfully to revenue for another year or two.