Code:
AREA_FLAG_SNOW = 0x00000001, // snow (only Dun Morogh, Naxxramas, Razorfen Downs and Winterspring)
AREA_FLAG_UNK1 = 0x00000002, // may be necropolis?
AREA_FLAG_UNK2 = 0x00000004, // Only used for areas on map 571 (development before)
AREA_FLAG_SLAVE_CAPITAL = 0x00000008, // city and city subsones
AREA_FLAG_UNK3 = 0x00000010, // can't find common meaning
AREA_FLAG_SLAVE_CAPITAL2 = 0x00000020, // slave capital city flag?
AREA_FLAG_UNK4 = 0x00000040, // many zones have this flag
AREA_FLAG_ARENA = 0x00000080, // arena, both instanced and world arenas
AREA_FLAG_CAPITAL = 0x00000100, // main capital city flag
AREA_FLAG_CITY = 0x00000200, // only for one zone named "City" (where it located?)
AREA_FLAG_OUTLAND = 0x00000400, // expansion zones? (only Eye of the Storm not have this flag, but have 0x00004000 flag)
AREA_FLAG_SANCTUARY = 0x00000800, // sanctuary area (PvP disabled)
AREA_FLAG_NEED_FLY = 0x00001000, // only Netherwing Ledge, Socrethar's Seat, Tempest Keep, The Arcatraz, The Botanica, The Mechanar, Sorrow Wing Point, Dragonspine Ridge, Netherwing Mines, Dragonmaw Base Camp, Dragonmaw Skyway
AREA_FLAG_UNUSED1 = 0x00002000, // not used now (no area/zones with this flag set in 3.0.3)
AREA_FLAG_OUTLAND2 = 0x00004000, // expansion zones? (only Circle of Blood Arena not have this flag, but have 0x00000400 flag)
AREA_FLAG_PVP = 0x00008000, // pvp objective area? (Death's Door also has this flag although it's no pvp object area)
AREA_FLAG_ARENA_INSTANCE = 0x00010000, // used by instanced arenas only
AREA_FLAG_UNUSED2 = 0x00020000, // not used now (no area/zones with this flag set in 3.0.3)
AREA_FLAG_UNK5 = 0x00040000, // only used for Amani Pass, Hatchet Hills
AREA_FLAG_UNK6 = 0x00080000, // Valgarde and Acherus: The Ebon Hold
AREA_FLAG_LOWLEVEL = 0x00100000, // used for some starting areas with area_level <=15
AREA_FLAG_TOWN = 0x00200000, // small towns with Inn
AREA_FLAG_UNK7 = 0x00400000, // Warsong Hold, Acherus: The Ebon Hold, New Agamand Inn, Vengeance Landing Inn
AREA_FLAG_UNK8 = 0x00800000, // Westguard Inn, Acherus: The Ebon Hold, Valgarde
AREA_FLAG_OUTDOOR_PVP = 0x01000000, // Wintergrasp and it's subzones
AREA_FLAG_UNK9 = 0x02000000, // unknown
AREA_FLAG_UNK10 = 0x04000000, // unknown
AREA_FLAG_CAN_HEARTH_AND_RES = 0x08000000 // Wintergrasp and it's subzones
// 0x20000000 not flyable?
Taken from http://www.madx.dk/wowdev/wiki/index.php?title=AreaTable.dbc
This might help you, even though some of them are still unknown...