When Toula presents her father's journal to Peter, she opens it to a random page, but then the scene is cut to the next scene, and Peter has to open the journal himself.
At 51:39 you can see a crew person in the background.
When they arrive at Greece and exit the airport, the scenery outside is not from the actual airport, but from the center of Athens. Athens International Airport is located 33 km southeast of Athens, at a suburb called Spata.
At the start of the film, the family is flying from Chicago to Athens. As they are outside the airport, the yellow cab has a New York tag.
When they finally arrive on that small ferry boat to wherever they were going or which island? it shows a small scene from the port of Agios Nikolaos City in Crete, Greece.