Green’s Dictionary of Slang

(US) an automobile.

1916		L. Pound ‘Word-List From Nebraska’ in DN IV:iv 271: blixen-bus, n. Automobile. ‘There comes the blixen-bus over the hill.’.
1928		Van Den Bark ‘Nebraska Sandhill Talk’ AS IV:2 132: An automobile is a ‘blunder-bus’ or a ‘blixen bus.’.