Pamplona's street bus website (
https://www.infotuc.es) is one of the most incredible ones I've ever seen. It can tell you what time a bus is scheduled for every stop on every line and what time you can expect to arrive at your destination stop.
Using it I could not set the date to May 28th (too far in the future) but for May 14th, still a Tuesday, a bus leaves the airport every hour, on the hour, from 7:00 to 22:00 and the one at 14:00 should get to the bus station at calle Yanguas y Miranda, nº 19 at 14:16.
There is also line 16 but it doesn't stop at the airport, it passes it by. You would need to walk out the approach road to the main street and then walk some ways north (on the left) or to the south (to the right) to a stop (I haven't been there but using Google Street View and Maps I would go south to Noáin, c/ Real (Merindad de Tudela) ) The bus should be there at 13:09 and every 12 minutes after with a 17 minute trip to the bus station at 13:50.
And then there are taxis.
For the interactive line 16 schedule for May 14 visit