Is it alright to let my caged Finches go outside with me in warm weather while still in their cage?

I have two finches that I recently bought. It's becoming spring here where I live and it will get warmer soon. I was just wondering if anyone would know if it was safe enough or harmful in any way to let them accompany me outside for a few moments while still inside their cage? Should I worry about their reactions to other bird noises, or seeing other birds by any chance? Sounds of cars or trains in the distance? Someone please help me. I just thought that maybe they would enjoy the fresh air and the warmth of the outdoors.