plane traveling with the curvature of the earth.

[pusswa]

does a plane automatically know to descend a little bit when travelling vast distances - where the earth curvature would be bending the further you go.

[PhilT]

To expand on the previous answer; once planes have left the vicinity of an airfield they all set their altimeters to the international standard pressure of 1013mb. This means that all en-route aircraft use the same pressure to determine their altitude, rather than local pressures which can vary from as low as 950mb to 1040mb. As everyone is flying around using the same datum, you can be sure that standard vertical separation between aircraft can be maintained.

[pusswa]

ok cool - thanx - i always wandered - cus if you look at the distance from London to Cape Town in SA - its a huge distance - and its a huge bend too! thanx alot!