First time traveling by plane – concerned about short connections at Newark

I have been in the situation a few times. What I did (and it worked):

Tell the in-flight personnel that you are anxious about your connection. In a decent reputable airline they will contact the airport and warn them that you may be late.

Once you get there, run for it. Have your ticket in your hand. Every time you hit a queue, run to the front and say "help, my flight is already boarding" Look worried. People will let you through and cheer you on. At every barrier ask the official to hold your flight for you. They probably will. People love to help.

On the outbound trip to the United States. I have a layover of 1h and 50 minutes at Newark Airport. I travel with the ESTA and I carry a checked bag, is it enough time?

If the airline sold you the ticket, they think it’s enough time.

I’ve never been through EWR myself, but based on experience elsewhere most airlines tend to be a bit optimistic, especially when it comes to handling of entry control and customs in the US. Assuming things work well, you should be fine, but if your flight from Madrid is delayed significantly, you may have to run, or may end up missing the flight out of EWR.

However, if you do miss the flight out of EWR, just talk to the airline’s customer support staff and they should be able to rebook you on the next flight free of charge. If you end up having to wait a day you can usually get reimbursed for the cost of accommodations for the night, and depending on the airline they may even help set things up for you.

I don’t know what to do when I get to the airport. Do I have to pick up my luggage and check it in again to get on the other plane?

There should be explicit signage in the airport, as well as airport staff directing you to where you need to go.

Standard practice for entry control in the US is:

• From the plane, you’ll be lead to the US CBP inspection area to go through customs declaration and entry control. This may be quite a walk from where you get off the plane, so be prepared for that. Things tend to move reasonably fast as long as they have enough staff (EWR should have a reasonable number of staff for this unless you’re arriving really early in the morning or really late at night), though as a non-citizen you will probably have a longer and more involved process. Note that US import law is very picky about certain things, though as long as you’re not carrying in any food, plants, or seeds you should be fine.
• Once you’ve cleared entry control, you’ll be directed to a baggage claim area to pick up your checked bags. Make sure your checked bags still have the tags on them from when you checked them in Madrid, without those tags you will have to go through a more complicated process to re-check them for the next flight.
• For non-citizens there may be additional steps here, but I would not know what they are in your case (I’ve never had to deal with them myself, and never flown with anyone who has).
• You’ll then follow the signs for connecting flights, which should lead you to an area to re-check your checked bags. Make certain you pay close attention here, as taking a wrong turn may end up with you ‘outside’ of the airport and needing to reenter and go through full check in and security. If you’re not sure where to go, don’t hesitate to ask airport staff.
• After checking your bags, you’ll go through a TSA security check.
• Once all that is done, just follow the signs to the correct terminal and gate for your flight. Make sure to double-check the departures boards in the airport to confirm what gate you should be going to.

On the return trip, the layover in Newark will be 1 hour. Will I have time now to take the plane from Newark to Madrid?

Probably fine as long as your flight to EWR does not get delayed (and even if it does, the airline should still be able to help you reschedule). Unlike most of the world, the US has no exit control, so the transfer in this case will just involve walking from whatever gate you arrive at to whatever gate your next flight is at. The gate agent for the outbound flight will probably check passports and any other mandatory travel documents to confirm that you will be able to clear entry control back in Europe, though this is usually done as you are boarding.

One more thing since you’re new to flying: When you check your bag they will put a paper tape on the handle. When you pick up your bag at EWR do not remove that tape–without it they will not recheck your bag. Some airports have counters there that can print a new tape, some will make you go out to the regular check-in points. The tape is only to be removed once you have arrived at your final destination.

You already have a connection I would not book, do not do anything that would slow you down! If everything works as it should you’ll be fine, but I’ve seen flight times deviate by 10% due to the jet stream and that’s completely outside the airlines’ control.

Also, there’s a good chance the boarding pass for the second flight doesn’t even have a gate printed on it, but even if it does that is not to be trusted that far out, check the boards and see what gate your flight actually is at. (This is unlikely to be a problem on your return flight as your boarding passes will be printed much closer to flight time.)

Trip from Madrid to USA: 1hr 50 mins might not be enough as you will have to go through immigration. And if the line is really long you will miss your connection. At SFO airport, many times I have seen a queue as long as 3 hours (except for US Passport, green card holders and Global entry).Also 1 hour 50 mins means you will have in hand at max 1 hour 15 mins because boarding starts early .

Trip from USA to Madrid: 1 hour may be fine but very tight. Ideally a 2 hour layover would be fine.

Note: This is based on my past experience and Newark airport seems to be a pretty busy airport.

On the outbound trip to the United States. I have a layover of 1h and 50 minutes at Newark Airport. I travel with the ESTA and I carry a checked bag, is it enough time?

Pretty tight, but if the airline sold you the ticket they think you can make it. If your inbound flight is delayed or there’s a mess at the immigration at EWR, you might need to run.

I don’t know what to do when I get to the airport. Do I have to pick up my luggage and check it in again to get on the other plane?

Yes, in the US you’ll need to go through customs at the first airport. After you go through the immigration, pick up your luggage, go past the customs, and check it back in again. Follow the "Connections" signs to get to the right place. See this interactive map of EWR to know where to go.

On the return trip, the layover in Newark will be 1 hour. Will I have time now to take the plane from Newark to Madrid?

Yes, since you don’t need to go through any customs or immigration, if there are no delays you’ll make it just fine. You may not have much time to spend at the airport, not that you’re missing anything at EWR.