Tisseo manages the public transports in Toulouse, their site (english version) is at the following address: https://www.tisseo.fr/en
Buying Tickets
Physical Tickets can be bought in any subway station or inside a bus directly (in this case only cash is accepted).
Contactless payment inside bus is also available and does not give you a physical ticket.
Using the Bus 27
This is the easiest way to get to the campus from the city center as one of its stops is directly in front of the main entrance.
From Jean Jaurès, one must go to the "Matabiau Gare SNCF" bus stop (right in front of the Matabiau train station) and take the bus in the direction of "Ramonville", then get off at "ISAE Campus Supaero".
The itinerary on tisseo can be found here
Using the Subway
The B subway of Toulouse has a couple of stops in the city center such as "Jeanne d'Arc", "Jean Jaurès", "François Verdier" and "Carmes".
One must take the subway in the Direction "Ramonville", then get off at "Faculté de Pharmacie", a 10min walk will get you to the main entrance of Supaero.
The itinerary on tisseo from jean jaurès can be found here