NEW YORK (AP) — AeroVironment Inc. shares plunged almost 25 percent before Wednesday's opening bell on worries that the defense company's profits and sales could continue to tumble this year as a result of lower government demand.

After Tuesday's closing bell, the Monrovia, Calif.-based company announced lower-than-expected quarterly results, blaming delays in government orders, and said that it expects those delays to seriously hurt its financial performance for the year.

AeroVironment said it thinks the lower sales are due to delays in order timing, not lost sales. But the company said it recalibrated its order and shipping expectations for the U.S. and cut its fiscal 2013 earnings and revenue guidance.

KeyBanc analyst Michael Ciarmoli backed his "Hold" rating for the company, saying that the weak quarterly results and lowered guidance weren't unexpected, but that he was surprised by how severe they were.

Ciarmoli noted that of all the defense companies he covers, AeroVironment is one of the most concentrated in a few select programs and products. He added that the end of the war in Afghanistan and defense spending cuts will likely reduce demand for AeroVironment's systems, reducing his confidence in his long-term earnings predictions for the company.

The analyst said that while some investors may feel compelled to buy shares at a discount following Tuesday's news, he would first like to "see the dust settle," along with the fiscal 2014 defense budget, before deciding whether to pick up shares.

AeroVironment shares dropped $5.39, or 24.9 percent, to $16.30 with about 15 minutes to go before the market opening.