I know a lot of people would like to be able to view competitor pricing on various routes. I know they would also like to peek in on LF% for those routes as well. While in real life I'm sure airlines have plenty of info on competitors' pricing, they may have less when it comes to LF%. I can understand why this information is not broadcast in the game as it would make price wars too easy.
However, I think a penalty mechanic could be put in place to add risk to anyone seeking this information. Basically, any player could order their Marketing Department to do a Market Survey of a particular route. Duration could set so that you can get a one day snapshot of whomever flies that route. This would be cheap, but given existing levels of variance it wouldn't be supremely accurate. Accuracy could also be heavily affected by the morale of the marketing department. Of course they could make the duration much longer, but at a heavy cost.
Prices should be somewhat prohibitive and will be impacted by duration, and the size and activity on the route.
I think that by making this information by request and at a cost, you give airlines information, but with added risk. The risk being that they paid money for it and what is true today is not necessarily true tomorrow. To add a layer of risk, perhaps all players on a given route could be alerted when any other player orders a market survey on that route.