United Airlines is set to announce an order for 110 aircraft from Boeing (NYSE:BA) and Airbus on Tuesday.United Airlines is set to announce an order for 110 aircraft from Boeing (NYSE:BA) and Airbus on Tuesday.Categories: 737 MAXA321 narrowbody jetsAir travelAirbusAircraft salesAircraft shortagesAirlinesbloombergboeingBoeing 787 DreamlinersBusinessEmissionsFranceJefferiesjetsPandemic restrictionsReutersSingle-aisle planessupply chainTodays HeadlinesTravel demandunited airlinesUnited Airlines' balance sheet