Stop going to visit them so often or at expensive times if you don't enjoy it and they don't enjoy it.

Also, I read your other post and is there any chance your mom might be gay? Maybe she is angry when she visits because she feels she is having to play family and suppress her true self and really wants to be with her girlfriend?

Honestly OP you sound immature. I don't know how old you are. You expect your parents to come and not talk abotu aches or pains, not to be tired after a transatlantic flight, and to be energetic and peppy regardless of how they are feeling. You wnat your dad to choose you over his wife and not to help her with her shoulder injury. You have told her how to treat it and she didn't listen so it sounds like you don't think she should have any support yet you wanted support from them for your own shoulder injury. You don't want your mom to have other friends at home because that takes the focus off of you...

I feel like part of this problem is the lens through which you view your parents. It is kind of like you are a teen annoyed that your parents aren't who you think they should be. You are still focused on how they treated you as a child and your resentment about that. You might find therapy helpful to try and reframe your view of your parents and to see them as adults making choices separate from them as parents. You may need to reset your expectations and figure out what you want from people you have as parents, rather than the people you wish you had as parents.

Lots of us had imperfect parents who now live their own lives and make different choices than we would.

OP, part of being a grownup is realizing that your parents are individuals, not just parents. Your mother can go away for the weekend with a friend rather than making her weekend all about your phone call. Your father can attend to your mother's needs rather than making his life about your needs. You are not a young child. Your parents are not going to live for you. Indeed, you and they are at a stage of life when you need to be thinking more about their needs and they may be more dependent on you.

I'm sorry, but you come across as very needy and very entitled to attention all the time. You live a transatlantic lifestyle. Elderly parents are not going to be able to easily adapt to that. It's a sad thing, but it's up to you to accept it. Your post has "grow up" all over it.

I am the OP of this thread.
I stopped responding when some people mentioned I wasn't being understanding and caring enough and that it was normal that my dad would feel that he had to stay and take care of her.
In the last month, when I have souled with my parents, twice my mom was gone for a long weekend with a girlfriend.
Don't know what my dad thinks about it, haven't had the chance to speak to him. He is quite useless with the computer and it is hard to Skype just with him. I emailed him but he is not good at that either. Anyway, this is not the point.
I wish he would just come and visit by himself.

I think traveling to Europe 2xyear is a bit too much. Spend this money on a really good nanny who will love your kids! Your parents can visit when they feel like it.
I have a useless annoying mother and a father who enables her (and enabled when we were small). She will never let him visit alone, and having her over will be such a drag and very little joy and even less help. I keep inviting them but don't visit much and I keep listening to their excuses for not coming.