Prior to October 1992 when the US Air Terminal opened, the airline operated from what is now the United Airlines
finger in the main passenger terminal with some spillover
into the American Airlines terminal. All US Air and Express flights were operating from the main terminal.
The Shuttle Terminal was built by Eastern Airlines in
the late 1970's and was designed to house Eastern
Air Shuttle Operations. To my knowledge, Continental
did not finance what eventually ended up being the
US Airways terminal given that they were in Chapter
11 for the second time in 1990. However, it is likely
that Eastern might have been planning to terminal
and Eastern and Continental were sister carriers for
a while under the Texas Air banner from 1988 to
1990 when Eastern folded. So, it is possible that
CO inherited the project and abandoned it in favor
of developing Newark into a hub, the operations
it acquired from PeoplExpress.
The US Airways Terminal is indeed the prettiest
and most airy terminal at the otherwise awful
LGA Airport. It is spacious and well appointed,
given the lack of space at the airport and it is
a decent enough place to spend the hours you
often encounter experiencing delays when you
fly out of LGA.