I've come upon the following information in my search for knowledge of AC and Belize. The paragraph below talks about a $75.00 US security fee. Is this something we have to pay??
A departure tax of $20.00 US is charged when leaving Belize (but not for intransit passengers who have spent less than 24 hours in the country); this must be paid in cash or travellers' checks (credit cards not accepted for departure tax). Further, travellers entering Belize International by air and connecting to in-country flights are charged a $.75 US security fee. When crossing the Western border between Belize and Guatemala for visits to Tikal and Flores there is a $3.50 charge to depart Belize (but this figure is then deducted from the departure tax when finally leaving from Belize from the International Airport). The visa charge to enter Guatemala at the Western Border is $5.00.