Originally Posted by
shawneve
In my situation all segments are classified as Business, three on AC, and one on UA. This implies that the UA flight has 3 classes because it let me book a Business seat. However Seat Guru tells me it will be a 2 class plane.
No, some UA domestic flights have I and O seats, even though they are 2 class planes.
These are usually flight numbers that have the same flight number as international flights. In your case UA201 is actually ORD-HNL-GUM.
This allows UA to book people in business, even though it is a 2 class plane, ensuring those people who paid business are up front.
Since there was an I bucket available because UA201 is an international flight - Aeroplan booked you in business class - even though this is a domestic 'first' aircraft.