It depends on how the game plays. As Halo gameplay stands (in multiplayer at least), the maps and 16 player gametypes are not large enough to warrant the use of a pelican... It would be able to carry the whole team, lol.
But if reach changes the formula a little bit and has a larger focus on bigger battles than 16 players (say, 32, or 48 like perfect dark zero/resistance 2), then I see no reason for the pelican to not be in the game.
[Edited on 10.16.2009 1:19 PM PDT]