Is the front of the plane packed?

If you actually meant "place" instead of plane, then yes there are times where both park entrances can be very packed. Usually at opening and just before the after work guests show up around 5. If you indeed did actually mean plane, the answer is no because a plane is only 2 dimensional and thus cannot be packed as it has no volume

Yes

Went this week on 25-26 dec. And the place was full, more people on Disneyland park than in california adventure but lines on both parks where not so slow but we cannot enter indiana jones or radiator springs racers.

The lines move relativity quickly.

I've never had to wait too long to get into the parks, but sometimes once you're in, they're totally packed!