can someone explain something to me about the international date line when travelling by air?

how is it that is travelling from west to east by air the journey you lose a day when crossing the internatoional date line but at the same time you arrive 2 days later.

i`ve been looking at flights and if you leave on say the 1st you arrive on the 3rd how can this happen if you lose a day

How long is your plane in the air- without figuring in the dateline thingy? A day? Lose another day to bring it up to two.
I suspect that you switched your directions- whenever I travel west to east, I gain a day. Which eventaully means that although I've been awake for 30 hours straight, it's still the same &£@@%* day. Traveling west loses the day.

It's just that the new day has to begin somewhere. The day is really continuous- the sun never goes out anywhere on the planet at the end of the local "day."

You're looking at the tickets in the wrong direction. Traveling from Australia to the US, you typically arrive at about the same local time as you left. Traveling from the US to Australia, you get there two days later local time.