Something smaller than starship (but with raptor, say) would fly briefly for a couple few minutes boost far away from the front line and head back down quickly.

Something smaller than starship (but with raptor, say) would fly briefly for a couple few minutes boost far away from the front line and head back down quickly. It wouldn't get near hostile airspace, but it's projectiles will. Moreover 3D printed engines (which other rocket companies are developing) are cheap enough that you could absorb some losses.