Please read the following table in HTML format from a webpage and then answer the question in detail according to the table. Each table cell is defined by a <td> and a </td> tag. Each table row starts with a <tr> and ends with a </tr> tag. 'rowspan=m' and 'colspan=n' represents a cell spaning over 'm' rows and 'n' columns.

Webpage title:
Nordic Air
Table title:
Fleet
Table:
<table id='hittask' contenteditable='False'>
<tr> <th colspan=1 rowspan=1 > Aircraft </th><th colspan=1 rowspan=1 > Quantity </th><th colspan=1 rowspan=1 > First in </th><th colspan=1 rowspan=1 > Last out </th></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > Douglas DC-4 Skymaster </td><td class="highlighted"  colspan=1 rowspan=1 > 1 </td><td class="highlighted"  colspan=1 rowspan=1 > 1970 </td><td colspan=1 rowspan=1 > 1972 </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > Lockheed L-188 Electra </td><td class="highlighted"  colspan=1 rowspan=1 > 2 </td><td colspan=1 rowspan=1 > 1972 </td><td class="highlighted"  colspan=1 rowspan=1 > 1973 </td></tr>
</table>
Question:
What were the airplanes operated by Nordic Air in the early 1970s?
Answer:
Nordic Air operated from 1970 to 1973 with a Douglas DC-4, and later with two Lockheed L-188 Electra.