The flyer's minimum movement of 18" complicates the requirement that it arrive within 6" of a unit of infantry or a ground vehicle coming in from the table edge. The flyer can't come on to the table from the same point as an infantry unit since it would outpace them. If it accompanies a vehicle, the vehicle has to move at cruising speed to keep up with the Stormtalon and is therefore of limited use. If the Stormtalon comes onto the table some distance away from the escorted unit's entry point in order to end its movement within 6", it will most likely have to stop at an angle that could leave most of its weapons facing away from the enemy.I've found a number of forums where posters also assume that the rule requires the flyer to stick close to the escorted unit.
However, when I read the slightly revised Escort rule in Death from the Skies and then reread the rule in White Dwarf, I realized that I had misunderstood it. Here's what the "Aerial Assault!" issue of White Dwarf said about the Escort rule:
If this is done [i.e., escorting], do not make reserve rolls for the Stormtalon. Instead it arrives at the same time as the unit it is escorting. The Stormtalon must move onto the board within 6" of the point that the unit it is escorting entered by. [emphasis mine]The phrases "must move onto the board" and "the point that the unit it is escorting entered by" indicate that the rule has nothing to do with where the Stormtalon or the escorted unit end their movement, but with where they begin their movement. In the rulebook, a phrase such as "move onto the table" refers to the beginning of a unit's movement as it arrives from reserves. And "the point that the unit it is escorting entered by" is so obvious that I'm embarrassed that I misunderstood it. I had been reading the rule as if it said 'the Stormtalon must end its movement within 6" of the escorted unit' when the models could actually end up relatively far apart as long as their starting points were within 6" of each other. My prior complaint about escorting infantry or vehicles was invalid.
Now that I understand the rule, I can see why the revised version found in Death from the Skies prohibits the flyer from escorting outflanking units. I found on several forums that some players had been assigning a Stormtalon to escort an outflanking unit and then using the Escort rule's requirement that the two points of entry be within 6" of each other to allow the Stormtalon to outflank as well.