Planar and interleaved are YUV pixel formats. Firstly, clarify that YUV pixel formats have 3 planes: Y (luma) - like gray scale, U and V (croma) - colors. These formats have various plane ordering.
The YUV components in planar format are grouped together. For example, the I420 format has the next group of components Y1 ... Yn U1 ... Un/4 V1 ... Vn/4.
In the interleaved format only the Y component is the same as in planar, but U and V are interleaved: Y1 ... Yn U1V1 ... Un/4Vn/4 (NV12 format).
In addition, component order depends on subsampling.