The aeroplane is heading NOrth. The Earth horizontal component is vertically down. Consider an electron in the wingspan acting like a rod. Using Fleming's LHR , the force on the electron is to the left side. The electron forced to the East wing tip will make it a negative potential , giving you the same result as using induced e.m.f method.
Note: The electron in the wingspan moving moving North require the current to point south(into the pic) when using LHR.
