Business Trip Write Off

[Kevin Franklin]

I purchased a ticket in December for a flight in mid-Jan strictly to visit one of my properties and attend a seminar.  Would this be a tax write-off for my 2019 tax return?  Also wondering if the expenses incurred during the trip (rental, hotel, etc.) can be a write-off toward this return as well or my 2020 return since the incidentals will actually occur in 2020.