There does not exist a United Airlines plane produced by Boeing.
All commerical aircraft are produced by either Boeing or Airbus. All American Airlines jets are commerical aircraft.  Airbus made more in revenue than Boeing last year.
∀x (CommercialAircraft(x) → ProducedBy(x, boeing) ⊕ ProducedBy(x, airbus)) ∀x (AmericanAirlinesAircraft(x) → CommercialAircraft(x)) MoreinRevenue(airbus, boeing)