The public bus to the Merida bus depot requires you to walk from the terminal to the main road - a long walk (or take the taxi).
If you need to get to Campeche, the best way to tavel is to take a taxi from the Airport to the CAME bus depot on Calle 70 (between 69 & 71). Buses run every half hour, take 2 hrs 20 mins. and cost about 152-180 pesos for first or deluxe class (there are 2 separate bus depots on Calle 70).
ADO's ticket sales are located on the upper level of the rminal, For more ADO informatio open ado.com.mx, e-mail firstname.lastname@example.org - tel. (999) 9-46-4790.