United Airlines Boeing 727-22 N7020U (msn 18312) OKC (Christian Volpati Collection). Image: 911753. Copyright Photo: United Airlines Boeing 727-22 N7020U (msn 18312) OKC (Christian Volpati Collection). Image: 911753. Share this:EmailFacebookLinkedInTwitterPocketRedditTumblrPinterestLike this:Like Loading...