Qantas will fly its ageing Boeing 747s on some domestic services to help cover gaps caused by a shortage of pilots, as the airline struggles to train enough to fly its fleet of workhorse 737s. The airline will operate 747 jumbo jets on up to 4 services a day between Sydney and Perth starting July 30 to cover for 737s, and will also replace 737s with larger A330s on some Perth-Singapore services to take pressure of its stretched workforce. The shortage of pilots who can fly Qantas' 737s - the dominant aircraft in its fleet, with 75 in operation - is being exacerbated by the introduction of 14 Boeing 787 Dreamliners to Qantas' international operations, with the majority of pilots being trained to fly the ultra-long-haul aircraft coming from its 737 workforce. <br/>