My itinerary paperwork stated that I could have a personal item. When I checked in with the ticket agent, I checked a rolling duffel and planned to take my pack on the plane as my personal item which fit within their chart for a personal item. It also met the 14x9x22 dimensions. The ticket agent insisted that I had to check this pack and was not allowed to take it on the plane as my personal item. United charged me $40 for this pack solely based on the type of ticket I purchased which showed "Economy", but, the itinerary I received from Expedia stated that I could take a personal item on the plane which this pack clearly me United's definition size chart as a personal item. Very dissapointed that I had to incur this additional expense.