The usage of a trainer jet like Hawk is to ensure that trainees doesn't have to directly go from a subsonic fighter to a super sonic fighter....What matters most is how much tolerance does the aircraft shows towards human errors....So its not the age of design that matters the most.....Trainers can be equppied to fight, but that won't be the major consideration at all.......What is needed most is the upgradation of avionics and sofwares which are generally done.... Structural defects too will be taken care in the upgradation.. So even though the Hawk name is old, it is a proven trainer...........