Airbag for oblique vehicle impacts

An airbag module includes a base and an airbag supported by the base. The airbag is inflatable from an uninflated position to an inflated position and presents an impact surface spaced from the base in the inflated position. The airbag includes an extension having a perimeter surface extending transversely from the impact surface around a perimeter of the extension. A tether extends from the base to the extension in the uninflated position. The extension catches the head of the test dummy if the test dummy slides along the impact surface during a vehicle oblique impact to slow and/or stop movement of the head of the test dummy toward a driver side door and/or A-pillar of the vehicle.