A hypothetical simplistic calculation.

Suppose you take a typical route, say
EWR-LAX or ORD-SFO on a A320.

Does anyone have the right set of assumptions to determine what the total revenue on that plane has to be to break even for UA? Assume that these routes are not subsidizing other low yield routes but just accounting for the proportional cost of running the airline.

I am trying to get a feel for whether the average price on a full plane needs to be in the order of $150/seat or $600/seat or $1200/seat to justify continued existence of UA.

Any brilliant accountants out there?