AI Startup Flapping Airplanes Is In Talks To Raise Funding At A $5 Billion Valuation

Flapping Airplanes, a research-focused startup that’s trying to find ways to use less data to train AI models, is in talks to raise capital at a $5 billion valuation, multiple sources familiar with the deal told Forbes. VC firms Index Ventures and Lux Capital are leading the round and Kleiner Perkins is participating, the sources said. The raise is in the hundreds of millions, they added.

Flapping Airplanes did not respond to Forbes’ request to comment. Index Ventures, Lux Capital and Kleiner Perkins declined to comment.

The San Francisco-based startup was cofounded in 2025 by brothers Ben Spector, 25, and Asher Spector, 26, and Aidan Smith. In January, it raised a $180 million seed round that included Sequoia Partner David Cahn, who later described Flapping Airplanes in a blog post as the “young person’s AGI lab.”

That’s a flattering label — and a bet. Flapping Airplanes is trying to wrangle one of the more daunting technical challenges of the current AI wave. Today’s most powerful AI models require training on vast pools of data to function well. The human mind manages to learn and reason from far less. The company is developing AI training methods that don’t need to ingest so much data, according to its website.

The San Francisco-based startup is among a growing group of so-called “neolabs” — companies that raise large sums of capital right out of the gate to do frontier research instead of building products or making revenue in the near term. Others like Ineffable Intelligence, founded by Google DeepMind researcher David Silver, are trying to solve similar data-related problems. The London-based company raised $1.1 billion to train AI that doesn’t need human data at all, instead learning through trial and error.

“While we are not currently trying to commercialize, our work will ultimately unlock enormous value in enterprise settings, robotics, trading, scientific discovery, and much more,” Flapping Airplane’s website explains.

The team behind the company is young and talented. As a PhD student at Stanford University, Ben Spector ran an incubator called Prod that helped founders of high profile AI companies like Cursor, Decagon, Etched and Decart (Spector and Cursor CEO Michael Truell were early collaborators). Smith, a Thiel Fellow, spent three years working at Neuralink while studying at Georgia Tech. The startup was on the Forbes AI 50 brink list in April.