I need to do a visa run but as im am still doing some extra work for my school for another month andI am now only on the free tourist visa on arrival, crossing a land border and coming back gives me only 15days now. I need 30, is it just the same if I fly to Kuala Lumpur and come back in the same day, and flying in gives me 30 days?

Entry by air is normally 30 days. Such entry can not be used for work so be aware you could be arrested at any time.

Arriving by air will give you 30 days. Applying for a free tourist visa at a Thai Consulate will give 60 days.

Also you are working illegally and face a fine, prison, deportation.