Joby Aviation, Inc. (JOBY) shares plummeted over 8% in pre-market trading on Wednesday, extending a recent downtrend as investors grew increasingly wary of the electric aviation startup's soaring cash burn and consequent risks of share dilution.

The electric vertical take-off and landing (eVTOL) aircraft maker reported a staggering $156.7 million operating loss in its latest quarter, primarily driven by research and development expenses. With cash reserves of $737.8 million, Joby can sustain these losses for roughly a year, but analysts warn that management may need to resort to further equity issuance, potentially diluting existing shareholders' stakes.

Joby's plans to raise up to $300 million through an "at-the-market" stock offering, following a $202 million equity raise just two months ago, have further fueled investor concerns. While the company has made technical progress in its pursuit of eVTOL aircraft and air taxi services, the capital-intensive nature of its ambitious plans is overshadowing near-term achievements and giving investors pause.