[mudman]

Their website says:

Carry-on baggage for worldwide travel
For worldwide travel on United (including travel within the 50 United States, Puerto Rico, the U.S. Virgin Islands and Canada), you may carry on one bag and one personal item such as a purse, briefcase or laptop computer. Your carry-on bag
must fit under your seat or in the overhead bin;
should not be more than 9 x 14 x 22 in. (23 x 35 x 56 cm) (length x width x height) or 45 linear inches* (114 linear cm); and
may be required to travel as checked baggage if the bag cannot be safely stowed on a particular flight.

So what counts as a briefcase? Can it be a small bag? I'm away for 5 days but not checking any luggage. Any other travel tips appreciated, I don't fly that often.

Thanks!