If the statement All aeroplanes are polluting vehicles is given as true, then which of the following statements can be immediately inferred to be true?

Some aeroplanes are polluting vehicles follows at once when the A proposition is true.

The given statement All aeroplanes are polluting vehicles is a universal affirmative A.

Its subaltern is the particular affirmative I, Some aeroplanes are polluting vehicles.

By subalternation the truth of the universal guarantees the truth of the particular.

This inference down the square of opposition holds for the A to I relation.