It could be a grand affair with elements from both their cultures. Aang being an Air Nomad, there might be floating lanterns and gentle wind chimes. Katara, from the Water Tribe, could have a beautiful ice sculpture as part of the decor. Their friends from all over the world would come to celebrate. Zuko would be there, of course, representing the Fire Nation. The ceremony would likely take place near a body of water, with Aang wearing his traditional Air Nomad robes and Katara in a stunning Water Tribe wedding dress, perhaps with blue silk and white fur accents.
Aang and Katara's wedding would be a grand affair. All the four nations would come together to celebrate. Aang, in his traditional Air Nomad robes, would be waiting nervously at the altar. Katara, looking stunning in a Water Tribe inspired dress, would walk down the aisle with Sokka by her side. The ceremony would be filled with elements of both Air Nomad and Water Tribe traditions. There would be chanting of ancient Air Nomad prayers and the pouring of Water Tribe ceremonial water. Their friends, like Toph, would be there making jokes and adding a touch of humor to the otherwise solemn occasion. And as they exchange vows, the whole world would seem to hold its breath, for this was a union that symbolized hope and harmony between the nations.
During their wedding, there could be a display of bending. Aang might create a gentle breeze that ruffles Katara's hair and dress in a beautiful way. Katara could make a small, intricate ice sculpture as a symbol of their union. Their friends would give heartfelt speeches. Sokka might tell a funny story about how he knew they were meant to be together from the start. Toph would probably use her earthbending to create a unique seating arrangement for the guests. And at the end of the day, as the sun sets, Aang and Katara would take a flight on Appa to start their honeymoon, with the cheers of their friends and the well - wishes of the four nations following them.
Their wedding would be a grand affair. It would likely be a blend of their two cultures. There would be water tribe traditions like the giving of special tribal gifts. Aang, being the Avatar, would probably have representatives from all the nations present. The air nomad traditions might include a special chant or ceremony to bless their union. And of course, there would be a huge feast with all kinds of delicious food from both cultures.
One sweet scenario could be that Aang surprises Katara with a display of his airbending skills, creating beautiful patterns in the air that symbolize their love. Then they share a passionate kiss.
Well, it might feature them in a beautifully decorated room. Aang could be giving Katara a special gift, perhaps something he made during their travels. They would talk about their hopes for the future, like starting a family. And they would end the night with a gentle embrace, looking forward to the days to come as husband and wife.
Zuko could be the best man. He has a deep respect for Aang and has become a close friend. His presence would also symbolize the newfound unity between the Fire Nation and the rest of the world. As for the maid of honor, maybe Yue. Even though she's no longer alive in the physical sense, her spirit could be present in a way. She was an important figure in Katara's life, and it would be a very emotional and spiritual choice.
Their relationship could deepen as they share in the joys and sorrows of rebuilding the world. They've been through a lot during the war, and now they can truly rely on each other. They might become even closer friends at first, with a mutual respect for each other's abilities growing stronger.
In some cases, the anger could be a catalyst for a more romantic development. Aang expressing his strong emotions might make Katara realize the depth of his feelings for her. Or it could be the other way around, Katara's reaction to his anger could make Aang see her in a new light, leading to a shift in their relationship dynamic towards a more romantic one.