Prophet Muhammad (ﷺ) never carried clean earth to perform tayammum while on journey, but these days Muslims usually carry it to perform tayammum in the plane. Is this permissible?

I don’t know of any evidence which supports the carrying of the earth in order to perform tayammum. So what they should do is do tayammum by hitting on the chairs (seats) if there are some traces of dust, if there is no dust then they should perform the prayer as they are “even if they are not clean”[1]

Allah knows best.

Reference:

[1] http://islamqa.info/en/10798