Would there be any issues trying to return to Mexico by plane?

Unless there are outstanding concerns of the US government, you would likely face no problems in leaving the US inasmuch as the Trump administration is actively encouraging undocumented immigrants to leave. Anecdotal evidence of people expecting problems at the airport shows that they are not being given trouble in departing. CBP has also developed a feature called “Intent to Depart” on its mobile app which allows individuals to officially announce their voluntary departure plans. Due to the limitations of the Lawyers.com Forums, Alan Lee & Arthur Lee, Esqs.’ (the "Firm") participation in responding to questions posted herein does not constitute legal advice, nor legal representation of the person or entity posting a question. No Attorney/Client relationship is or shall be construed to be created hereby. The information provided herein by the Firm is general, and requires that the poster obtain specific legal advice from an attorney. The poster shall not rely upon the information provided herein as legal advice nor as the basis for making any decisions of legal consequence.