Doesn't look any more cramped than the back seat of a car.
Translation, it's going to cost more than $20.
Try LA to Sydney in coach.
Plus, with a car you'd have a 7-8 hour journey to look into.
And with an (equally cramped if not worse) plane you'll have more traval time than in this scheme, if you include waiting to depart, the lengthy procedures at the airport and getting to the airport in the first place.