Here's a map of the supposed flat earth. Given that it's flat, there should be no distortion, so sizes and distances should be proportionally correct:
https://images-na.ssl-images-amazon.com/images/I/617nAsDfXNL.jpg
It looks like the distance from coast to coast in Australia is about twice the distance from coast to coast in the US.
But, the distance from Perth to Brisbane, which is close to the east-west axis of Australia, is 3606 km. Don't believe it? Ask a friend to take the flight, or ask one of the many many people who have taken that flight how long it takes.
https://www.distancecalculator.net/from-perth-to-brisbane
Maybe airplanes actually can travel
much faster than "they" say. Okay, drive on the roads. Or ask a friend who has. The driving distance is 4312 km.
The distance from Seattle to New York, which again seems to be pretty much the east-west axis, is 3870 km by air and 4589 km by car.
Not only is Australia
not twice as long from one side to the other as the US, it's actually shorter. Any flat earther can actually go and test this himself if he wants to uncover the conspiracy.