A donut might fit, but not an emergency tire.
There are several threads here discussing this.

 

Nope won’t fit tried it, and the donut wouldn’t be strong enough for the weight of the car.

 

The trunk can definitely hold one full size spare, but it will take up a decent amount of your trunk space.
I wanted to bring a spare with me for my road trips, but did not end up bringing it, because there would be no space for my other stuff

 

I hope EVs realize they need add a jack and spare back to the cars soon. The area under the hood on top would make the most sense to be molded for use as spare or storage.

 

I hope EVs realize they need add a jack and spare back to the cars soon.

Why specifically EVs? My last 3 cars didn't have spares?

 

Yes all cars, but I said EV since no ICE under hood.

 

The wheels on EVs are massive compared to ICE, putting a space is adding serious weight to the car. Putting on a donut style wheel isn’t feasible due to the weight and I’m not sure but can you damage the motor by driving with two different size wheels on the same axel?

I’m not sure if you have seen what’s under the hood @davenport but the P2 doesn’t have a lot of space there. The MY24 may have more, but still not enough for a 19in Wheel.

 

I was thinking it would be on an angle lower in the front. The air could be vacuum-deflated if necessary, but the more likely solution would be to cut the inner width down and keep the radius the same.
When you corner, one wheel is rotating at a different speed than the other, the same as if one wheel was slightly smaller.
I realize no spare is going to fit into our front compartments now, but could in a future design. Airless tires will also be developed to save weight.