paypal pending payment?

I just booked, or tried to book, my flight to the US in June. The payment with the credit card failed for unspecified reasons, though it may well be the case that it is because my monthly spending limit on the credit card is too low (it's quite low, but I didn't use it that much this month, so really I think it should have been okay). Then I tried the paypal option and it seemed to go through okay. I received a confirmation e-mail and everything. However, the payment status on paypal still says "pending", and I have no idea what that means. Does it mean that paypal is still checking with my credit card whether the funds are actually covered? If so, I might be in trouble, because I am not sure that they are (the credit card automatically gets paid off at the end of each month, so it's not like I'm in debt or anything, but again, the monthly limit isn't very high). Or is it just a formal process that is taking a little longer? I forget how paypal works exactly in this regard, and the "help" page gives me a funny error message (the gist of which is: the help page isn't yet available in English, please switch your language preferences to English) and is thus no help at all.