Out of Luton, working for Monarch, we used to sometimes tanker fuel to Sharm on a good day but on a wet, low pressure day (particularly if below 10'C or hot) then there could be limitations, the NEO's improved fuel consumption would reduce these limitations. The Configuration of Monarch A321's is 214 seats. The A321 wing rather than the engines tends to be the limiting factor on the A321. Flights to Boston would also require a significant amount of extra weight in te form of "ETOPS" fuel.