[Guest]

If your worry is just in terms of having spare planes, then you may well have the same issue with Virgin, although a bigger airline, their fleet is almost at capacity usage. I'd go with the cheapest - in all honesty the amount of times a plane goes out of service is to few to get worried about, and if it's a maintenance issue it's likely all planes are susceptible to the same issue so having more may not necessarily be a good thing