Passengers traveling with United Airlines can make their travel experience a remarkable one by making an upgrade. One of the suitable ways to make an upgrade is using the UnitedPlus miles, and it depends on the seat availability. If you are regularly traveling with the airline, you can get a United Airlines First Class Upgrade complimentary from the airline, depending on the class of your flight. Also, you can place a bid for a seat with PlusPoints, giving you the chance to get a first-class seat at a lower price. It provides a more comfortable journey, with access to lounges at the airport, priority boarding and delicious meal options.