A4 is smaller than letter. I don't see a requirement to print it on A4, but you might want to ask the consulate. I'm looking at this form, and it should print fine on letter size:

http://www.esteri.it/visti/pdf/Formu...chengen_EN.pdf

With the full disclaimer that you should ask the consulate - the primary motive for asking to see entry and exit transportation and lodging information is to obtain evidence that you do not intend to overstay your visa. Demonstrating that you've paid to enter and leave, as well as a place to stay, helps Italy understand your plans and how you intend to live and support yourself during that time (given that you can't work). I doubt they can or want to hold you to your lodging plans, but those are good questions to ask. As far as flights, I presume you're asking about side trips within Schengen, not your flights to/from Schengen? The consulate's primary concern is your dates and plans to exit Schengen and from where.

How strict they are on the documentation is likely going to have to do with your propensity to overstay based on demographic info, as well as the risk based on your country of origin/residence/citizenship.