DETROIT — General Motors and Honda say they have signed a deal to explore sharing vehicle underpinnings and propulsion systems in North America.

The companies say planning discussions on jointly designed vehicles will start immediately and include vehicles powered by both electricity and internal combustion engines. Engineering work would begin early next year.

Honda and GM say in a statement today that they’ll also cooperate on purchasing, research and connected services.

The memorandum of understanding between the companies isn’t binding. But the move is another sign of increasing consolidation in the automotive business as companies face huge capital outlays to develop products as well as new electric and autonomous vehicles.