To join in Air Force you can also apply for AFCAT Exam, you can also apply for NDA Exam.
You can join army through CDS Exam.
As technical candidate, you can join Army, Navy or Air Force. But you have to face the entrance exam for this.
1) Short Service Commission (Technical) : Age limit is 20 to 27 Years.
2) Qualification : Engineering degree. Selection through direct SSB Interview.
3) Short Service commission : Engineering degree. Age limit 19 to 25 Years.
4) For Air Force Qualification : BE / B.Tech / Degree with PCM.
You can also apply for CDS Exam. these exams are conduct by UPSC.