Firstly, Thai registered, MJets Cessna 750 Citation X HS-KCS is shown below. The Citation bizjet had a busy day Thursday, starting the day in Townsville, and then flying to Mackay, then Emerald, and then Gladstone. HS-KCS departed Gladstone for Brisbane.
Also noted at Gladstone Airport on Thursday 31 May, was Gulfstream G550 (G-V-SP) N661CP.
What a great way to celebrate - thanks Jamie!