There have been some not insignificant trades in Aer Lingus shares in the last couple of days. They're up 5% today even after what I considered slightly disappointing results (abou 5-10 million wider than I anticipated) and were also up yesterday.
I'm not sure Ryanair are allowed to buy at the moment, but even if they aren't someone seems to be gambling on another bid.
Correct Ryanair are pretty much at their limit in terms of buying and any purchase automatically triggers another bid and would have to be disclosed.
It can't even be a group acting on behalf (term is In Concert) with Ryanair in buying up shares as that is illegal following Guinness / Distilllers takeover.
Potentially its a few hedge funds taking a position.