According to reports, Melania Trump's plane experienced a "mechanical issue" on Wednesday.

First Lady Melania Trump's plane was reportedly forced to return to Andrews Air Force Base on Wednesday morning.  Trump was on her way to Philadelphia to meet with families whose children were impacted by opioid exposure in the womb.  According to CNN, the plane began to fill with a smoky haze about ten minutes after takeoff. The plane landed safely and the source of trouble has been identified as a mechanical issue. 
ABC News reports: "A source described it as a 'minor technical issue' and that the first lady was 'fine.'"