As the gig economy continues to expand, opportunities for informal and short-term work are appearing in many sectors. And while some seek the flexibility and a chance to earn extra money, others are finding project-based work is a great way to gain experience in a new field.

Far more than just odd jobs and driving for Uber, gig economy jobs are now expanding in white-collar professions and the skilled trades. Chris Reffett, senior vice president with MS Companies, says workers can even find day assignments with industrial companies, advanced manufacturers and high-tech firms seeking to meet their labor needs. Much as project-based gigs enable employers to "test drive" workers, these opportunities allow workers to see if such industries or careers are right for them, Reffett says.

"People can try a job, industry or something that has always been intriguing to them and do it without a [long-term] commitment," Reffett says. "It benefits both companies and workers."

MS Companies connects gig workers with major employers in the automotive, consumer goods manufacturing, energy and tech industries. Reffett says many companies are seeking to supplement their seasonal demands with additional labor, also giving workers the opportunity to try a day at positions that have historically only been open to full-time workers.

On platforms such as Upwork.com and Freelancer.com, organizations also are now hiring accountants, web developers, marketing managers, business writers and finance professionals on a project basis. Despite the perception that gig workers are there by necessity because they lack full-time opportunities, many professionals say freelancing can offer greater flexibility, better pay and more security than a traditional job.

A recent study by Upwork and the Freelancers Union found that 60 percent of freelancers are working in the gig economy "by choice" and that half would not go back to a traditional employment.

New graduates, retirees and others are finding gig projects that can help them gain experience to get a foot in the door in a new career. Allison Robinson, founder and CEO of The Mom Project, says the gig economy has been a valuable stepping-stone for moms that are seeking to re-enter the workforce or find a new career.

"Project-based work is a great way to explore new ​career paths and can help women maintain professional relevancy and earning potential through periods when they may have otherwise felt their only option was to leave the workforce altogether," Robinson says.