An airbag (110, 210, 310) comprising: a base panel defining an inflator opening with which an inflator for delivering inflation gas into the airbag can be coupled, the base panel comprising a top end and a bottom end, wherein the base panel is configured to be mounted to a vehicle such that the top end of the base panel is at an upper position and the bottom end of the base panel is at a lower position, relative to the vehicle, when the airbag is in a deployed state; a cushioning panel attached to the base panel and cooperating therewith to define an inflatable chamber; and a deflector (140, 240, 340) positioned between the base panel and the cushioning panel and covering the inflator opening of the base panel, wherein the deflector cooperates with the base panel to define: an inflation cavity; a first lateral inflation aperture (182, 184) configured to direct inflation gas out of the inflation cavity in a direction having components in a first laterally outward direction and in a downward direction, without a component in an upward direction, during deployment of the airbag; a second lateral inflation aperture (182, 184) configured to direct inflation gas out of the inflation cavity in a direction having components in a second laterally outward direction and in the downward direction, without a component in the upward direction, during deployment of the airbag, wherein the second laterally outward direction is opposite of the first laterally outward direction; and a lower inflation aperture that is closer to the bottom end of the base panel than is the inflator opening, wherein the lower inflation aperture is configured to direct inflation gas out of the inflation cavity in the downward direction toward the bottom end of the base panel during deployment of the airbag. a base panel defining an inflator opening with which an inflator for delivering inflation gas into the airbag can be coupled, the base panel comprising a top end and a bottom end, wherein the base panel is configured to be mounted to a vehicle such that the top end of the base panel is at an upper position and the bottom end of the base panel is at a lower position, relative to the vehicle, when the airbag is in a deployed state; a cushioning panel attached to the base panel and cooperating therewith to define an inflatable chamber; and a deflector (140, 240, 340) positioned between the base panel and the cushioning panel and covering the inflator opening of the base panel, wherein the deflector cooperates with the base panel to define: an inflation cavity; a first lateral inflation aperture (182, 184) configured to direct inflation gas out of the inflation cavity in a direction having components in a first laterally outward direction and in a downward direction, without a component in an upward direction, during deployment of the airbag; a second lateral inflation aperture (182, 184) configured to direct inflation gas out of the inflation cavity in a direction having components in a second laterally outward direction and in the downward direction, without a component in the upward direction, during deployment of the airbag, wherein the second laterally outward direction is opposite of the first laterally outward direction; and a lower inflation aperture that is closer to the bottom end of the base panel than is the inflator opening, wherein the lower inflation aperture is configured to direct inflation gas out of the inflation cavity in the downward direction toward the bottom end of the base panel during deployment of the airbag. an inflation cavity; a first lateral inflation aperture (182, 184) configured to direct inflation gas out of the inflation cavity in a direction having components in a first laterally outward direction and in a downward direction, without a component in an upward direction, during deployment of the airbag; a second lateral inflation aperture (182, 184) configured to direct inflation gas out of the inflation cavity in a direction having components in a second laterally outward direction and in the downward direction, without a component in the upward direction, during deployment of the airbag, wherein the second laterally outward direction is opposite of the first laterally outward direction; and a lower inflation aperture that is closer to the bottom end of the base panel than is the inflator opening, wherein the lower inflation aperture is configured to direct inflation gas out of the inflation cavity in the downward direction toward the bottom end of the base panel during deployment of the airbag.