Obviously, the ripple has grown due to the airdrop expectations on December 12, when the SPARK tokens will be handed out for holding ripple. I think this is not yet the peak of Ripple's growth, I'm waiting for it at $ 1 and I will sell there.
I do agree with your statement, sudden gain in ripple price has happened because of the airdrop thing, all the XRP holders would able to get SPARK token airdrop. That's must be the reason behind XRP's price spike. As well if BTC crosses the $ 20k mark then again it will get momentum in its growth and it could be reached to $1 price.