Vehicle airbag

1. A vehicle, comprising:

a seat having a seat bottom and defining a seat-forward direction;

an interior component;

an airbag supported by the interior component and inflatable to a first inflated position having a main body elongated along a vehicle-longitudinal axis extending in the seat-forward direction and an extension extending from the main body transverse to the vehicle-longitudinal axis in front of the seat bottom relative to the seat-forward direction; and

a tether fixed to the extension and a tether release operatively coupled to the tether;

wherein the airbag is inflatable to a second inflated position having the extension inverted into the main body and extending vehicle-rearward before the tether is released.

2. The vehicle of claim 1 , further comprising a processor and a memory storing instructions executable by the processor to actuate the tether release based on a direction of a detected vehicle impact.

3. The vehicle of claim 1 , further comprising a processor and a memory storing instructions executable by the processor to actuate the tether release based on a detected occupant size.

4. The vehicle of claim 1 , further comprising a processor and a memory storing instructions executable by the processor to inflate the airbag and then actuate the tether release.

5. The vehicle of claim 1 , wherein the airbag in the first inflated position is L-shaped after the tether is released.

6. The vehicle of claim 1 , wherein the extension is at a front of the main body relative to the seat-forward direction.

7. The vehicle of claim 1 , wherein the interior component is a door.

8. The vehicle of claim 1 , wherein the interior component is a center console.

9. The vehicle of claim 1 , wherein the extension extends in a cross-vehicle direction.

10. The vehicle of claim 1 , further comprising an instrument panel, the extension of the airbag in the first inflated position between the seat bottom and the instrument panel.

11. The vehicle of claim 10 , further comprising a second airbag supported by the instrument panel and inflatable to an inflated position above the airbag in the first inflated position.

12. The vehicle of claim 1 , wherein the extension is spaced from the seat bottom in the seat-forward direction.

13. The vehicle of claim 1 , wherein the seat bottom defines a centerline, and the extension extends toward the centerline.

14. The vehicle of claim 1 , wherein the airbag is supported below a vehicle-beltline.

15. The vehicle of claim 1 , wherein the airbag in the first inflated position is completely below a vehicle-beltline.

16. The vehicle of claim 1 , further comprising a second interior component and a second airbag supported by the second interior component and inflatable to an inflated position having a second extension, the extension and the second extension extending toward each other.

17. The vehicle of claim 16 , wherein the interior component is a center console and the second interior component is a door.

18. The vehicle of claim 17 , wherein the extension in the first inflated position abuts the second extension in the inflated position.