Print all Country Codes
Python 2, 240 bytes

Straightforward binary encoding implementation.

R=range(26)
print"\n".join(" ".join(chr(65+r)+chr(65+c)if int("8hfxckgq1olihfa47x3rrdkojzkklec7qk1hp4ht6avmzxfg7c4uv14xe0pzvvg93x81ag2bf88v2w0p3p08g8nwtuktbwosj9dytset3qmhdl72v5u62nepapgabdqqu7x",36)&amp;1&lt;&lt;c+r*26 else"  "for c in R)for r in R)


The script for generating the integer is quick and dirty:

codes="""AA    AC AD AE AF AG    AI       AL AM AN AO AP AQ AR AS AT AU    AW AX    AZ
BA BB    BD BE BF BG BH BI BJ    BL BM BN BO    BQ BR BS BT BU BV BW BX BY BZ
CA    CC CD    CF CG CH CI    CK CL CM CN CO CP    CR CS    CU CV CW CX CY CZ
            DE    DG       DJ DK    DM    DO                            DY DZ
EA    EC    EE EF EG EH             EM       EP    ER ES ET EU EV EW         
                        FI FJ FK FL FM    FO       FR                FX      
GA GB GC GD GE GF GG GH GI       GL GM GN    GP GQ GR GS GT GU    GW    GY   
                              HK    HM HN          HR    HT HU               
   IB IC ID IE                   IL IM IN IO    IQ IR IS IT IU IV IW IX IY IZ
JA          JE                      JM    JO JP                              
            KE    KG KH KI          KM KN    KP    KR             KW    KY KZ
LA LB LC       LF       LI    LK                   LR LS LT LU LV       LY   
MA    MC MD ME MF MG MH       MK ML MM MN MO MP MQ MR MS MT MU MV MW MX MY MZ
NA    NC    NE NF NG    NI       NL       NO NP    NR    NT NU             NZ
OA                                  OM                                       
PA          PE PF PG PH PI    PK PL PM PN          PR PS PT       PW    PY   
QA                                  QM QN QO QP QQ QR QS QT QU QV QW QX QY QZ
RA RB RC    RE       RH RI       RL RM RN RO RP       RS    RU    RW         
SA SB SC SD SE SF SG SH SI SJ SK SL SM SN SO       SR SS ST SU SV    SX SY SZ
TA    TC TD    TF TG TH    TJ TK TL TM TN TO TP    TR    TT    TV TW       TZ
UA                UG          UK    UM                US                UY UZ
VA    VC    VE    VG    VI             VN                   VU               
               WF                WL       WO          WS       WV            
XA XB XC XD XE XF XG XH XI XJ XK XL XM XN XO XP XQ XR XS XT XU XV XW XX XY XZ
            YE                                           YT YU YV            
ZA                                  ZM             ZR             ZW       ZZ
"""
n = sum(1 &lt;&lt; (x/3) for x in range(0, len(codes), 3) if codes[x] != " ")
def baseN(num,b,numerals="0123456789abcdefghijklmnopqrstuvwxyz"):
    return ((num == 0) and numerals[0]) or (baseN(num // b, b, numerals).lstrip(numerals[0]) + numerals[num % b])
print baseN(n, 36)