Current path finding algorithm does not work well with shuttle

[patsonluk]

If 2 airlines A and B offer shuttle from same airport X to Y,

if to Y, the lower cost shuttle is from Airline A, then it will completely shut out B, which is not correct, as B might have flights going out from Y that either A does not offer or A has higher cost

Need to re-think path finding with shuttle - the main hurdle here is that shuttle behaves differently, pax cannot switch from airline A to B. Hence the lowest cost to node X algorithm is not going to work well here