The only people driving into Heathrow in older cars will be holiday makers.
No. Many staff who work at Heathrow drive older cars (me included, my car is 12 years old, works very well and is well maintained so should last me ages yet, but is not ULEZ compliant.) It has caused much annoyance among airport workers who live to the west of Heathrow. Thousands of airport workers live west, but the public transport systems seem to be oblivious to that. Trust me, if I could easily hop on a train or bus to commute, I would. However, even though Heathrow is well served by tube, it is the end of the line, and the only way you can travel onward from a Heathrow tube or train station is east - into the city centre. This more than doubles the cost and time it would take me to get to work. I did the sums, and it turns out the cheapest way to avoid the ULEZ charge is to actually buy a cheap little car. So I now have 2 cars. I am a long haul airline employee, but many workers like baggage handlers, terminal shop and hospitality staff, check in staff, and nearly all short haul workers will be coming in 4-5 days a week. It’s added about £900 a year to my expenses, for those travelling in daily from, say, Maidenhead or Slough it would add over £2000.
For the majority of those workers there isn’t really a public transport option that works. There are no buses or trains serving Heathrow from the west that will get you there for 5am, or get you home when you finish late at past midnight. Staff car parks are all on the perimeter roads, so it is not possible to park up outside the ULEZ and get a shuttle bus in.
Having to pay another £25 to go on holiday is slightly tiresome. But having to pay £1000s to just come into work is really bloody annoying.