But it means passengers will be limited to one small under-seat bag rather than up to two with a combined total weight of 7kgs. Some passengers were asked for their thoughts on Wednesday morning at Melbourne Airport and most were shocked by the changes. Camera Icon Jetstar passengers could be charged more than $50 for carry-on on flights. Credit: AAPFormer flight attendant weighs inFormer flight attendant Nicola Dale said the new scheme will only “hurt the customers”. The size limits for each option are up to 40cm × 30cm × 20cm for an under-seat bag, which is included in every fare.