water, snacks

All of the big international flights will provide a snack (usually a small bag of pretzels) and all the water and soft drinks, coffee and tea that you like. Beer, wine and alcoholic beverages are also free on some airlines, but not all. On United, for example, you'll pay $7.00 for each alcoholic drink. Only credit cards accepted, no cask.
The dinner, or main meal, on international flights is included at no extra cost to you, as is a breakfast snack shortly before landing.

John, You can take food through security (we bring sandwiches, fruit, and pretzels), but the water you'll need to buy at one of the airport shops after you get through security. You can't pass through security with any liquids greater than 3 oz, but your food will be okay. Enjoy Italy!

Sorry--only credit cards accepted, no cash.

After passing through security control, you can take your empty water bottle and fill it at the water fountain. It may be changing, but water, soft drinks, and some snacks were included (United Airlines). United also provides a meal shortly after take-off and another smaller meal shortly before landing. Check with your airline about drinks and food. There doesn't seem to be a standard for what is provided and what is not free.

John, As the others have mentioned, you shouldn't have any trouble with food items such as Pretzels or other "prepared" foods. Be careful with items such as fruits, vegetables or meats, as they probably won't be permitted in the country of arrival and will be "binned" as soon as you land. The water question is easy. When you've gone through security, go to the nearest shop and buy a bottle of water (about 500 mL is a good size and easy to carry). You can easily get that refilled on the plane or at a fountain in airports. You'll probably find that the flight crew comes through the cabin frequently offering water, as it's good to stay hydrated on long flights. One point to note however - if you have a connecting flight, you may have to go through security again. Be prepared to either drink quickly or dump the water, and then refill the bottle when you get through the checks. On flights to Europe, the airline will usually provide a full meal about two hours after departure, and then a "continental breakfast" about an hour before arrival. These are usually included with the cost of the tickets. I often travel with Air Canada, and they also provide complimentary wine with the meals (not sure if that's the same with U.S. airlines). There are two "schools of thought" on whether it's a good idea to consume alcohol or coffee on flights, but I find that one small bottle doesn't affect me adversely. Happy travels!

To add to George's post, other airlines that keep you fed and watered are Air France, British Air, Air Transat, KLM, Royal Air Morocco etc.

In the past year, I have flown both Delta (direct to Madrid from ATL) and Virgin Atlantic (O'Hare to Heathrow). Both provided meals and breakfasts at no cost. Virgin Atlantic also provides free wine, etc. (and ice cream bars on the way home). And both come through frequently with either water or juice.

In flying from Honolulu to Seattle on Hawaiian Airlines in May, 2013, a flight I take often, I was offered alcoholic beverages during the beverage service during the meal service. A first time event for sure. When asked, an attendant said it was a new HA policy. We will have to see if it stays.

John, as everyone is saying, what will be served depends on the airline, the route, and the class of service. The following refers to coach class. On almost all domestic flights, you get a free snack (small bag of pretzels or a cookie), and free non-alcoholic beverages. You can buy alcoholic beverages and various food items on board medium and large planes, but on commuter flights (the smaller jets or propeller planes, like most flights out of Harrisburg), they usually don't sell food. Of course, there are exceptions; Hawaiian Air makes a big deal out of the fact that flying from JFK to HNL, they still have an included meal (their competitor on that route, United flying from EWR to HNL, does not include a meal). On trans-Atlantic flights, dinner and breakfast are included. On US airlines, alcohol is often extra; on European airlines, it's usually included. Non-alcoholic beverages are complimentary on both. The big exception is Icelandair, where food and drinks are not included, but are for sale. Remember that these policies do change, so if it really matters to you, check your airline's website for details on your specific flights. Others have told you about the rules for bringing your own. Food can be brought on, but fresh produce must be consumed before landing in a foreign country. Liquids can only be brought on if they're bought after security, but most people find that you get enough fluids on the plane (particularly if you ask for extra water when they come around for coffee service). Unless you have dietary restrictions or a medical condition, it's usually not worth the trouble to bring your own food/drink on international flights, where you are getting fed. On domestic flights, I've taken to bringing Kashi bars (2 per "meal") and just letting the airline give me beverages.

I have been taking my own food from home on board international flights for decades. I have found that a small tupper wear dinner container with say coucous, fresh herbs, tomato bites and some cubed chicken tossed with olive oil and lemon juice gives me a much happier tummy and lots and lots less sodium. (Take a plastic fork /spoon.) Your taste buds are dulled when flying for a variety of reasons so the airline food industry bumps up the salt to make it taste better. I find herbs, lemon juice does the same thing salt free. No more swollen ankles for me. I also take a lightweight insulated water bottle (empty through security). I pay for a cup of water from a fast food joint and then fill my bottle up with ice water. So, take something to eat that's either spicy or tangy or both (my husband likes roast beef sandwiches with lots of horseradish). All this said on my last flight from Rome to Atlanta on Delta the breakfast was so good it was lucky I was sitting down and strapped in.