Your sister's jealousy feels like a separate issue from your mom's concern, lol. Is she maybe upset because she doesn't feel she has the same freedom in her own life? Unpacking that could be the real key to cutting the drama.
Have you explained to your sister why you take these trips alone? It's tough when family reacts that way, but they probably just miss you. Your mom's worry might calm down if you set up regular check-ins while you're away. You deserve to do things that make you happy without guilt. Maybe a honest chat about your needs could ease the tension.
Consider reframing this as a communication issue, not a travel problem. Their feelings are about missing you and fearing for your safety, not about the trip itself. A good talk about your plans and check-in routine might ease both the jealousy and the worry.