ɐdˈɪʃənəl plˈeɪnz kæn ˈɔːlsoʊ biː ʌnlˈɑːkt fɚðə mˌʌltɪplˈeɪɚ mˈoʊd bˈeɪst ˌɔn pɹˈɑːɡɹɛs ɪnðə sˈɪŋɡəlplˈeɪɚ kæmpˈeɪn.
Additional planes can also be unlocked for the multiplayer mode based on progress in the single-player campaign.