Australia has bought million dollar aeroplanes are they useless?

Can these aero planes be bought down by multiple gps radio controlled small aeroplanes.
Try this for a scenario big highly complex war plane up against 15 small agile fighters controlled interdependently but act as individuals. They turn quicker than missiles and go on the attack in the blink of an eye.
They are small probably similar in shape as the BD5 and about 2meters long.
These small planes use jet engines made from modified turbos from cars.
They have a high speed of say 500kph and a flying height of 45,000 ft.
They carry the smallest anti aircraft missiles of about a ft long or they themselves are the missile.
They are all weather capable and they can sit beside roads for weeks or months waiting for the right time to attack.
They can self distruct if tampered with.
They have the ability to spy on enemy movements even whilst on the ground.
They have stealth capacity and are made from wood and fibreglass.
They have a range of 800 kilometers.
They float when landed on water and can take off from water.

In conclusion they are made from commercially available parts found on cars and are easily manafactured in the back yard shed.
They use simple toy model plane - drone electronic systems.