Today's aerospace start-ups need to be on their toes because succeeding in this industry becomes increasingly difficult. For this reason many young companies rely on acquisition companies (Spac) that promise cosmic returns in the stock market. For example in the last three months a large company like Virgin Galactic lost 46% in the stock market after some Spac mergers of new creatures of founder Richard Branson. The latest is Virgin Orbit, born on December 30th, which debuted on Nasdaq last Friday.

The phenomenon affects the entire aerospace industry, which has fully embraced Spac mergers. In fact, another large company in the sector such as Joby Aviation, manufacturer of electric vertical take-off and landing aircraft (eVtol), has lost 31% on the stock exchange in recent months. The same happens in the more promising field of satellite launch vehicle construction companies: Rocket Lab and Astra Space remain richly valued, but analysts' projections have become much more cautious. 

Eve, the eVtol builder controlled by Brazilian aircraft manufacturer Embraer, also recently announced a Spac deal valued at 2.9 billion dollars, but it will have to battle with a host of competitors in a market that analysts say is now worth a trillion dollars. 

This situation represents a warning for aerospace startups. Aerospace Spac stocks can provide opportunities for bold investors, but fickle market sentiment will play a defining role in the fate of these young companies.