How can I signal to others on my flight that I want to make friends and chat?

Friendships begin on shared experiences and rely on reinforcement of those experiences, but there are specific places and times where people are receptive to starting friendships.

While flights satisfy the shared experience requirement, they don’t satisfy the reception requirement: people "tune out" on airplanes because the experience is uncomfortable — be it altitude, be it confinement, be it fear — and discomfort is not a mood that benefits new friendships.

Your best bet is to strive for conversation, not friendship, and to make overtures at the gate, not on the plane. As long as your overture is genuine — "I like your shoes", "That book looks interesting", "Did I see you here last month?" — people will start a conversation. Whether that conversation carries further than the gate will depend upon the interests you find you share and the dynamic between you.

Your shirt idea is too forceful. Your goal is too broad. Friendships are like fire: they start small, are kindled slowly, and nurtured to grow by feeding with the proper fuel. Proceed with an open mind and be genuine. You’ll likely find some connection, and maybe — just maybe — you’ll find a lifelong friend.

Allow me to suggest you work on the opposite question. Instead of asking How you can signal others? A better question would be How to recognize others who are interested in chatting?

There are all sorts of travelers and their interest and mood vary greatly. Whether you get to have a conversation with someone or not will be attributed to their disposition and a lot of luck. While on the flight, generally you will only have one or two neighbors. Even in the waiting area, there will only be so many people who are within the space where you can have a conversation at a comfortable volume.

First, look and observe casually people around you. There will usually people moving leisurely, looking around and smiling which will be easier to talk to. There will be others with shades, headphones and a cap, that would not be approachable. Many will be somewhere in between but on a long flight itself, expect a lot of people to be tired, sleepy, worried or annoyed. If they seem calmer, you will have an easier time talking. Personalities vary tremendously, so start with a casual comment and see the kind of response you get.

Minor disclaimer: I am an introvert! However, I have spent hours talking with people next to me dozens of times. Sometimes, I never hear from them again, while I have also made friends on planes and trains that I speak with regularly for over 15 years.

It was never my intention to make friends or even speak hours-on-end, and so you will probably manage well since it seems you are willing to put effort into it. As I said though, much of it is luck. It is easy to exchange a few words about the weather or the plane but you need to land on a common interest for the conversation to last for hours and it to reach the point where someone is interested enough to continue the conversation beyond the flight you are on.

Conversation willingness is also heavily cultural. There are usually mostly people from the countries you are travelling to and from, and some from nearby ones, so the culture of people around you will change quite a bit depending on your travel. In some cultures it is very common to casually talk to strangers while for others it is rarely done. Part of it could be reciprocal in that a person from a certain background might be more willing to chat with someone from a similar one but I only have my own perspective to observe with. From that point of view, I can see that anywhere from Central to South America plus West and Southern Europe people tend to be more willing to talk with strangers. In Northern Europe and Northern Asia, it is much harder to find people who are comfortable with it.

First, I don’t think a shirt is going to help much. For some people it will be too eager, a little weird even. For others, they aren’t going to read it. But let’s say someone reads it, believes it, takes it at face value, and wants to chat with you. Are you expecting them to come up to you and start a conversation? To do the work?

Second, I think you will find you are in a vanishingly small minority. I don’t know anyone who likes talking to strangers on planes. I am on my technology (or asleep) during my long flights because I would prefer to do that than talk to anyone. I am sure people exist who enjoy a good chat — I have seen strangers talk on cruises and ferries and tours — but it seems to be a "pass the time" thing for the trip and not the start of a beautiful friendship.

But, should you want to make a friend, and you’re prepared to accept that perhaps nobody on your flight shares that want, you are going to have to be the one to do the work. That’s going to mean smiling at people, greeting people, and saying things to people that our society uses to start conversations. "I love your earrings!" "Oh, I was thinking of seeing the movie of that book you’re reading, is it good?" "Did I see you working this same flight last week?" You need to be really sensitive to people not wanting to talk, and ready to leave them alone in that case, while at the same time being bubbly, outgoing, and warm. [Be especially cautious with flight attendants, who have to be friendly to everyone even if they do not want to do so, and with a seatmate or anyone else who may feel trapped and unable to leave if your attention is unwanted.] If the person is receptive at all, you can introduce yourself. You can say you fly this route a lot. You can ask them about themselves. It may take several shared flights before you feel a friendship is developing, or perhaps you’ll click with someone right away.

It might also help to have next steps available. For example, if you take a sightseeing day at the start of each trip for jetlag, you could invite your new friend to stroll some famous park with you. If you already have a cab to the city booked, you could offer to share it with the person. You can give them tips about great restaurants or bars or stores that you’ve found in this destination. Share your enjoyment of this destination with your fellow traveller. Or, if they are going home to the place you’re visiting, maybe let them share their knowledge with you.

All of this is work. But once you’re over 20, friendships grow from work. Not from Tshirts.

One other thing: you mention only wanting platonic friendships. Some people who are receptive to your greetings and conversation starters may be hoping for something non-platonic. Be alert for signs of that so you can make your intentions clear early on, and don’t escalate too quickly to "spending time alone in private places" with someone you’ve just met.