。
Should we walk, or should we drive?
Literal
Walk go [volitional-か] or-else car [with-で] go [volitional-か].
The casual volitional + か combo: 行こうか ('shall I / shall we go?') is the plain-form version of 行きましょうか. Two of these joined by それとも give a casual 'shall I do X or Y?' question with no polite endings.