YOU SAID:

the planes accomplished their mission

INTO JAPANESE

飛行機はその使命を達成しました

BACK INTO ENGLISH

Airplane has achieved its mission

INTO JAPANESE

飛行機は、その使命を達成しています

BACK INTO ENGLISH

The plane, has achieved its mission

INTO JAPANESE

飛行機は、その使命を達成しています

BACK INTO ENGLISH

The plane, has achieved its mission