AI lab Flapping Airplanes raises a $1 billion Series A, quadrupling its value in nine months

Flapping Airplanes, a San Francisco AI research lab, announced a $1 billion Series A on October 21. Index Ventures and Lux Capital co-led the round, with earlier backers Sequoia, GV and Kleiner Perkins participating; Nvidia is also an investor. Bloomberg reported that the round values the company at about $6 billion, a figure the company itself did not disclose. The lab launched in January with a $180 million seed round at a $1.5 billion valuation.

Aidan Smith and brothers Asher and Ben Spector founded the company in late 2025. It has no product on sale yet. Its goal is to train large models with far less data and computing power, and it says it has spent the past year developing new primitives for GPUs. According to Index, its megakernels run an entire program on a GPU as a single kernel, eliminating idle time between steps. The founders claim the framework can overlap memory-bound inference with compute-bound training, TechCrunch reported. The new money will go toward hiring and turning that goal into reality. Index partner Mark Xu is joining the board.