The maker of Pratt & Whitney jet engines, UTC, has agreed to buy airline parts maker Rockwell Collins for $30bn (£23bn).
The tie-up is one of the biggest deals in aviation history and is expected to be completed next year.
It has the potential to shake up the market for aerospace parts and could give UTC greater negotiating power over planemakers Boeing and Airbus.
Both planemakers have been pushing suppliers to lower their prices.
By making more aircraft components, analysts say, UTC will be in a better position to resist such pressures.
Pratt & Whitney jet engines are used by Airbus, Bombardier, Embraer and other planemakers, while Rockwell Collins is a major supplier to Boeing and Airbus among others.
Under the terms of the deal, UTC chief executive Greg Hayes will remain as CEO of the combined company.
He said: "This acquisition adds tremendous capabilities to our aerospace businesses and strengthens our complementary offerings of technologically advanced aerospace systems."
Rockwell chairman, president and chief executive Kelly Ortberg will run a new business known as Collins Aerospace that will combine the parts businesses.
The $30bn price tag includes Rockwell Collins' debt. Before the deal can go ahead, it will have to gain regulatory approval.