Is working for an airline company to repair airplane seats and connect audio cables (which include Quran recitations and music broadcasts), assemble food carts, aircraft wheels, and install shelves, unlawful, given that the company serves and sells alcohol and other products?

There is no objection to working in aircraft maintenance, repairing their seats, and installing their shelves. This is permissible in itself and has no connection to the company's provision of unlawful things. However, it is not permissible to do or assist in what is unlawful, such as serving alcohol.